Early Irish Monasticism and their Astronomers

Commentarii de Bello Gallico

In the first millennium, Christianity had a great impact on Irish Celtic society and British Roman-Celtic society. One of the most evident effects in the case of Ireland was the introduction of the habit of writing, an innovation of considerable importance as we know, as Julius Caesar also testifies in the Commentarii de Bello Gallico, that the Celtic Druids wrote absolutely nothing. things of religion. For the Celts, nature was a living and constantly evolving thing: writing meant freezing a concept, preventing its evolution, and therefore the druids tended not to write and if anything they did it with some reluctance.

Numerous writings commenting on the Holy Scriptures were produced in Europe during the first millennium. Of all the regions of northern Europe, Ireland was the most abundant source of writings, and this favoured the development of a conception of the Northern European high-medieval Church that we could define “hibernocentric” (from Hibernia, the name with which the Romans identified the never conquered Ireland). From this point of view, the Irish Church played a predominant role in the spread of Christianity on the European continent. For example, the sacrament of Confession exercised privately, that is, with the penitent confessing his sins in secret to the priest, was an innovation of the Irish Church that subsequently spread throughout the Christian world. Another example is the use of the word “parish”, which derives from an ancient Irish term used to indicate a set of tribes practicing Christianity not necessarily settled in neighbouring territories.

Chrismon Chi-Rho  is one of the earliest forms of a Christogram

However, scholars agree in recognising marked differences in the various ecclesiastical communities in various regions of the Celtic isles, for example between Britain, where the Anglo clergy was mainly of the Benedictine order, and Ireland, where the influence of Rome had almost always been non-existent. Christianity spread in Roman-Celtic Britain since the fourth century, coexisting with other religions in a markedly pantheistic society. For example, in Caerwent there was a small Christian community that coexisted without conflict with the remaining pagan population. In the immediate vicinity of the church of Caerwent, which dates back to the 4th century, archaeologists have found a large number of burials, astronomically oriented, placed along the equinoctial direction and associated with the presence of the ⳩ chi-rho or monogram, symbol of Christ, which according to some eminent French medievalists seem to enclose the symbolism of the four solstice directions and the meridian line.

The monk Gildas in his De Excidio et Conquestu Britanniae, which dates back to the V century, mentions the presence in the territory of monks, abbots and deacons, thus suggesting the existence of a well-organised episcopal Church and denouncing, among other things, its corruption and connivance with certain local tyrants. 

Christianity spread to Ireland initially through the work of St. Patrick. The fifth century, and part of the sixth, saw the presence of many Christian missionaries in Wales, Scotland and Ireland; many were the ascetics and hermits who retired to the mountains devoting themselves to prayer and meditation. Among the missionaries Palladio, coming from the church of Auxerre (in Gaul), sent by Pope Celestine to Ireland as bishop of the community of “believers in Christ”, as Irish Christians were called. His task was to counter the spread of the Pelagian heresy, spread by the monk Pelagius and his disciple Caelestius, who opposed Augustine of Hippo and his doctrine of original sin. The most famous exponent of the Irish Church in addition to St. Patrick was St. Columban, who founded throughout Europe a series of monasteries and places of worship of which traces remain even today. Columbanus arrived in Milan in 612 and was warmly greeted by King Agilulf and Queen Theodelinda of the Lombards; King Agilulf gave Columbanus a tract of land called Bobbio between Milan and Genoa near the Trebbia river, situated in a defile of the Apennine Mountains, to be used as a base for the conversion of the Lombard people. During the last year of his life, Columbanus received a message from the Merovingian King Chlothar of Neustria, inviting him to return to Burgundy, now that his enemies had all died. But Columbanus did not return. Instead he requested that the king should always protect his monks at Luxeuil Abbey. With the gold provided by Chlothar, who has always been a friend to Columbanus, he was able to found a Monastery at Bobbio near Piacenza where he died three years on November 21, 615.

Christianity was welcomed quite favourably by the Celtic peoples, as its spiritual character had many points in common with the traditional pagan religion: just think of the conception of death understood as a passage from one condition of life to another and to immortality. of the soul, concepts commonly held and taught by druids. Caesar himself in the Commentarii de Bello Gallico attributes to these convictions the substantial indifference to the danger of death in battle which characterised the Celtic warriors and which worried the Romans so much. The Irish monks were called “White Martyrs.” Irish saints had to forgo the bloody “crown of martyrdom” until the Viking invasions at the end of the 8th century. St. Jerome had used the term “white martyrdom” for hermits who aspired to the condition of martyrdom through strict asceticism. The Cambrai homilist elaborates also on a distinction made by Gregory between inward and outward martyrdom. White martyrdom (bánmartre), he says, is separation from all that one loves, perhaps on a peregrinatio pro Christo or “pilgrimage on behalf of Christ” that might be extended permanently; The first was the “white martyrdom”, which consisted in the complete abandonment of the outside world and all personal affections to enter the monastery, devote oneself to study and prayer and face the peregrinatio, that is the journey to evangelise distant lands. Green (or blue) martyrdom (glasmartre) involves the denial of desires, as through fasting and penitent labours, without necessarily implying a journey or complete withdrawal from life; red martyrdom (dercmartre) requires torture or death.

Dunloe Ogham Stone © Robert Linsdell

The Irish monks were the first to introduce the custom of shaving the hair, according to the ancient Druidic style, from the forehead to the top of the head, while letting the hair flow into the back of the head, the so-called “tonsure”. On the stone stems dating back to the Early Middle Ages we find inscriptions in ancient Irish drawn with the Ogham alphabet, in which the monks are called mael, that is “tonsured.” These religious preserved both the way of thinking and the attitude to observation and to the study of nature and its phenomena including astronomical ones, typical of the druids who for at least a millennium administered the pagan cult. These singular men of the church, including Caidoc, Fricor, Virgilio il which we will return to later), San Cathal (who became bishop of Taranto), toured the length and breadth of Europe, founding many monasteries around which important cities such as Lumieges, Auxerre, Laon, Luxeuil, Liège, Trier, Salzburg would later grow , Vienna, San Gallo, Reichenau, Bobbio, Fiesole, Lucca and others. Fiesole had a bishop “Scottorum sanguine creatus” for over half a century, that is, born of Irish blood: Donatus (Donnchad) the Erudite (attested 844, 861). Most of these personalities also produced astronomical writings, some of which are simple records of phenomena observed visually, while others are larger works. St. Patrick himself, who seems to have prayed to God by calling him in Old Irish Drui or Draoi (druid), wrote on astronomical matters. The “White Martyrs” pushed toward the East going as far as Kiev bringing their culture and that of the Latin classics which probably, without them, would have been destroyed.

In the year AD 870 the Carolingian priest and poet Heiric of Auxerre wrote: “Almost all of Ireland, despising the sea, emigrates to our coasts with a flock of philosophers” (Vita S. Germanus). The Irish friars were distinctly different from the monks, especially Benedictines, who lived in Italian, Spanish or French abbeys and monasteries, but also in Northumbria, in the centre of Great Britain. These characters, half friars and half druids, had a considerable interest in astronomy, due not only to the druidic substratum, but also to the fact that the Roman Church had established some very specific canons, based on the moon phases, for the calendar liturgical, for the date of Easter and for other religious occasions. The widespread use of astronomy in Ireland is testified by many writings produced in the first millennium.

Facsimile of a diagram in an astronomical tract (ca. AD 1400) in the Royal Irish Academy, Dublin. The lower small circle is the sun (sol): the middle smaller circle is the earth (terra), throwing its shadows among the stars.

Cormac Mac Cuileannain (836-908 AD), author of the famous Sanas Chormaic (Glossary of Cormac), wrote that: “Any intelligent person can estimate the time of night throughout the year by studying the position of the Moon and stars.” In the Saaltair na Rann (Psalter of the Staves or Quatrains, X century) we find written that “The educated people in Ireland must know the signs of the Zodiac with their names in the correct order, and the exact month and day on which the Sun enters each sign.” Emblematic is also the story of Saint Virgil (Virgil the Surveyor), abbot of Aghaboe, bishop of Ossory and later bishop of Salzburg. He was called “the Apostle of Carinthia” and “the geometer,” who was an Irish monk named Feirgil, educated in the monastery of Cainnech or Canice (famous, among other things, for teaching astronomy) whose astronomical works in AD 750 caused him some problems with the Aglo-Saxon Saint Boniface of Crediton (†5 June 754), known as Malleus Ecclesiae Celticae “hammer of the Celtic church” because of his resoluteness against the customs of the Irish and Welsh clergy relating to the cosmographic speculations of Feirgil ended up in the hands of Pope Zacharias di Santa Severina, who, however, agreed with the Irishman. Boniface of Crediton received a letter from the pope dated 1 May 748 stating that “there is under the earth another world and other men and Sun and Moon”; in other words, the pope accepted the idea of ​​the roundness of the Earth, and that it could also be inhabited at the antipodes, as Feirgil was saying. In contrast, the Venerable Bede († 735), a Benedictine of Northumbria, wrote explicitly: “Terra rotunda est” that the “Earth is Round” in his influential treatise on computus, De Temporum Ratione—The Reckoning of Time— seven centuries before Christopher Columbus (1451—† 1506) and the Disputation of Salamanca (1550–1551) 

Another illustrious Irishman was Dungal of Bobbio who, educated at the Abbey of Beannchor (Bangor Co. Down), observed the two solar eclipses that occurred in the year 810. The Holy Roman Emperor Charlemagne had asked for an explanation of two eclipses of the sun, said to have occurred in 810, and sought an explanation of it from the abbot of St. Denis, near Paris. He in turn wrote to Dungal, then known for his scientific attainments. Dungal accordingly wrote to the Emperor, giving him such an explanation as he could, of an event which actually never occurred. The rumour is supposed to have arisen from an erroneous calculation, predicting a double eclipse in 810. The letter, however, exhibits a considerable acquaintance with the astronomy of the day. Dungal was evidently not quite satisfied with the Ptolemaic system, and draws on his knowledge of the teachings of Macrobius, Pliny, and other ancient authors. This letter demonstrates “a knowledge of astronomy far beyond the current ideas of his time.” Dungal explained the phenomenon (always in a geocentric context, therefore with the Earth still and the Sun and the Moon physically moving around it) demonstrating that he knew well the mechanism by which the eclipse could be produced, the measure of the inclination of the plane of the Moon’s orbit with respect to the ecliptic and its periodic variation. The monk Dungal is believed to be the founder of a school that developed to later give rise to the University of Padua. We should also remember another famous Irish monk, Dícuil, and his treatise De mensura Orbis terrae a summary of geography, giving concise information about various lands, composed in 825, in which he hypothesised the existence of a “south polar star” opposite to the one observable in the northern hemisphere of the Earth. This work was based upon a Mensuratio orbis prepared by order of Emperor Theodosius II (AD 435).

Figure of the heavenly bodies — An illustration of the Ptolemaic geocentric system by Portuguese cosmographer and cartographer Bartolomeu Velho, 1568 (Bibliothèque Nationale, Paris)

In those days they regularly made use of mystical symbolism, especially solar, linked to the figure of Christ, and particular prescriptions relating to the position of the Sun’s rising point had to be respected in the construction of places of worship and for the burial of the dead. Archaeological finds and aerial reconnaissance techniques of the territory have highlighted traces of the closed curvilinear structures within which the first monastic settlements in Ireland and Britain were located: the construction and architectural criteria seem astronomically significant. In Ireland an enclosed monastic settlement or vallum can be found at Kilmacoo near Kanturk in County Cork, the site of which, bordered by a moat and a wall, shows the remains of a church built with dry stone and numerous astronomically aligned burials. The church and the tombs were accessible via a direct road to the sunrise point of the winter solstice. At that time (VII century) the winter solstice took place on December 18 of the Julian calendar, a date close to that on which Christmas Day had been celebrated. It is known and well documented that the winter solstice represented an important moment in almost all ancient cultures, even outside of Europe, so much so that it was celebrated with a ritualistic festival. The slowdown of the regression of the sunrise point, the inversion of its motion and the consequent, progressive lengthening of the days were a clear symptom that the winter season and the related survival difficulties were about to end. Christianity also made this concept precise, and the birth of Jesus was conventionally fixed close to the winter solstice. 

Aerial view of Nendrum Monastery, 2015.

Also in Ireland we find the great monastery of Nendrum, on Mahee Island in Strangford Lough, County Down, founded by Saint Mochaoi in the V century. The site, excavated by archaeologist H. C. Lawlor between 1922 and 1924, shows traces of a triple concentric ring of elliptical shape,  also called cashels (enclosures) of dry stone walls, inside of which there are traces of a stone church with the apse oriented according to a 55° azimuth, which corresponds to the direction of sunrise at the summer solstice on the local hilly horizon (remember that a 90° azimuth corresponds to East, 180° to the south and so forth). Each ring represented a delimitation of the sacred space compared to the profane one and therefore was invested with divine protection (this is a genuine Celtic tradition of pagan origins). The innermost ring had to include the church, the abbot’s house, the cemetery with its monumental crosses and the cloightech, the cylindrical tower with the conical roof typical of Irish monasteries. The outermost enclosures instead housed the buildings used as a granary, farm and artisan workshops. The entrances to the stone enclosures were always ritually placed to the east, in the direction of the rising sun. The tombs present in Nendrum are placed in front of the entrance to the church and oriented in the same direction as the church, as well as the skeletons found in them, considering the skull-pelvis direction. 

monastery of Inis Uasail, Oileán an Teampaill (Church Island) Lough Currane

In Inis Muireadheach (Inishmurry), is an uninhabited island situated 4 miles off the coast of County Sligo, here we find a large wall of approximately 80 metres in diameter inside which there is a stone church with the apse oriented in the direction of sunrise on the dates of the Celtic holidays of Imbolc and Samhain (see below). The enclosure wall is impressive — reaching 4.5 metres (15ft) in height at its highest point and up to 3 metres (9.8ft) thick. The site contains various ecclesiastical buildings including enclosures, a stone-roofed oratory, two churches, a clochán, a large beehive-shaped cell, a holy well and other remains including cross slabs suggesting foreign influences. The whole complex is composed of what is probably local sandstone rubble. Among the small towns we can include that very interesting monastery of Inis Uasail, Church Island, in County Kerry, also in Ireland, and was founded by Saint Fionán Cam (VI century AD). The monastery was developed in two distinct phases. The 33 burials grouped around the North corner of the remains of the church, belonging to the first phase, are distributed in such a manner that the skull-pelvis direction favours a line whose azimuth is correlated with the direction of the rising of the Sun on the dates of the Celtic holidays of Beltane and Lughnashad. The 8 burials grouped around the South corner date back to the second phase of development and are oriented at 86° of azimuth, practically facing the direction of the rising of the Sun on Easter calculated in the Celtic manner (before the Council of Orleans  decision was ratified, Easter, therefore, was placed 7 days after the spring equinox, contrary to what is prescribed by the Church of Rome). Passing from the first to the second phase, the orientation is according to the “Roman” criterion (equinoctial) which became common over the more ancient “Celtic” ones (Beltane and Lughnasad).

Sunrise-oriented tombs in Beltane and Lughnasad are also found at the remains of the ancient monastery of Dunmisk Enclosure, County Tyrone, the site is hugely significant in that it is also the first evidence we have of glass-making. Here it was also discovered that the site was home to a complex monastic settlement with a cemetery of over 400 graves. There is also Tulaigh Lis (Tullylish), County Down, where the Annals of Ulster indicate the presence of a monastic community from 809, the same year in which the astronomical phenomenon were also recorded (in very bad Latin), a “celestial fire,” probably the Northern Lights or perhaps the passage of a comet. 

Cross-inscribed stone, the large pillar stone on you left as you enter the site, is in its original position, and has been dated to the 2nd half of the 6th century.

Riasc (Reask), is another ruined early Monastic site located 1 km east of Baile an Fheirtéaraigh, County Kerry although nothing remains of the buildings but low walls and a cross-slab standing stone which sits in the middle of the compound. It flourished around the V to the X century and was then abandoned. There are no records of the early ecclesiastical site at Reask, but excavations which took place in the early nineteen seventies revealed an oval shaped enclosure with a cashel type wall. This wall is around 2.2 metres in width and at its highest point is about 1 metre high. Inside the walls are the remains of several Clocháin, a stone oratory, a rectangular structure and two other circular huts. Excavations also revealed a cemetery with over 42 lintel graves. Also revealed were a number of Ceallunach graves. Scattered around the site we find a number of cross slabs and pillar stones. Pictured left is a beautifully inscribed pillar stone decorated with a Greek cross in an inscribed circle with pendant spiral designs terminating in a pelta —from Greek πέλτη péltē, “Shield” of elliptical form or crescent-shape—. This stone stands at 1.65 metres high and just over half a metre wide. During the excavations it was noticed that here too the apse of the church is aligned with the rising sun on March 25, that would be on the ancient Celtic calculation of Easter  Day according custom. The numerous burials are similarly facing the East whilst the skeletal remains have their heads facing toward the West.

Gallarus oratory

At Reask the Gallarus Oratory, in Ballydavid County Kerry was built between the seventh and eighth century and is the best preserved early Christian church in Ireland. It represents an apogee of dry-stone corbeling, using techniques first developed by Neolithic tomb makers; it has the distinctive shape of an upturned boat which according to tradition should refer to the boat of Saint Brendan the Navigator. It is oriented along the equinoctial line, with the apse to the East, and is equipped with a single window above the altar from which the rays of the rising equinoctial sun entered illuminating the whole interior.

Sundial stone Kilmalkedar

Also in the Dingle peninsula we find Cill Maoilchéadair — Kilmalkedar a medieval ecclesiastical site on the Dingle Peninsula, 3 miles east of Ballyferriter, the largest and most important church in the area: traditionally associated with Brendan the Navigator (ca. AD 484 – ca. 577), the surviving church dates to the mid-12th century, with the chancel extended ca. 1200, and is astronomically oriented in accordance with the equinoctial sunrise. Some of the rituals carried out there by the locals, such as carrying out nine clockwise circuits of the site on Easter Sunday, or the boring of holes in standing stones, demonstrate the remnants of pagan Celtic rites; Kilmalkedar may well have been a religious site long before Christianity arrived in Hibernia. Near the church there is a (Fig. left) sundial (solam in old Irish), also dating back to the XII century. 

Saint Basil the Great declared in ‘On the Holy Spirit 27′ that “facing the east to pray was among the oldest unwritten laws of the Church.” The eastward direction of prayer among early Christians is a custom inherited from the Jews. At the time of the formation of Christianity, Jews commonly prayed not only towards the Temple of Solomon, where the “presence of the transcendent God.” Using the phrase ad orientem, Augustine of Hippo mentioned the practice at the end of the fourth century stating ‘When we stand at prayer, we turn to the east ad orientem, whence the heaven rises.” The uniform orientation towards the East when at prayer was due to the fact that within the writing of the church fathers of the IV and V centuries the faithful were directed to pray facing eastward, and the celebrant himself during the Actio Liturgica also faced the same direction. The Holy Celtic Church continues the practice of ad Orientem, whilst the Church of Rome now does the opposite and faces versus populum facing the people –and in certain parishes are omnidirectional–, practices which would have been severely frowned upon by the the Early Christian and Celtic Churches. 

Aerial reconnaissance also made it possible to identify the areas used as a cemetery only, where excavations have brought to light both tombs and skeletons. These structures, called llan in Old Welsh, generally contained a few dozen tombs; in the case of burials of people in the odour of sanctity, the tomb was placed in an isolated spot and the place was called merthyr (transposition of the Latin term martyrium: a place of worship built over relics of a martyr). The Christian tombs are recognisable as they were inhumed (entombed) and besides the deceased no burial gifts are found, whilst in Ireland and Britain the pagans generally tended to cremate human remains. 

The Christian burials are all astronomically oriented: the skeleton is arranged along the equinoctial line (east-west), with a deviation of 5° more or less, or along an azimuth line of 115-120°. The first equinoctial orientation was linked to the rising of the Sun on Easter Day computed in the Celtic manner, while the second orientation is in agreement with the rising of the Sun in the days when the Celtic holidays of Samhain and Imbolc fell. Of the two, Samhain was by far the longest and most important of all. All the skeletons were found with their heads to the West and feet to the East, so that the deceased could virtually watch the rising sun at dawn. Not only the tombs, but also other Irish places of worship, built roughly around the middle of the first millennium, show a distribution of orientations along some privileged directions. There are two cardinal directions: the meridian direction (north-south), which is very rare, and the equinoctial one (East-West) with the apse facing east. The others are much more interesting as they coincide with the positions of the rising of the Sun on the dates of the four main festivals of the pagan Celts, namely Samhain, Imbolc, Beltane and Lughnasad. However, an interesting fact should be pointed out: in ancient times these festivals were celebrated in correspondence with the heliacal rise of some important stars for the Celtic culture of the Iron Age. Samhain and Beltane, celebrated respectively in November and May, corresponded to the heliacal rising of Antares and Aldebaran and defined the beginning of the Celtic year, of the period of “darkness,” that is of the winter season (Samhain), and of the period of “light,” ie summer (Beltane). In fact, among the Celts, the seasonal division of the year was not based on the Sun, but on the stars. The festivals of Imbolc and Lughnasad did not delimit any seasonal period, but were rather agricultural and social festivals: Imbolc was dedicated to the pre Christian goddess Bríg. The pagan sun god Luɣ, , Lug or Lugh one of the most prominent gods among the Irish Celts and is equated to the Roman god Mercury. Lámhfhada, is linked with the harvest festival of Lughnasadh, which bears his name, also instituted Assembly of Talti an event very similar to the Greek Olympic games which finished on August 1 (Lughnasadh) in memory of his foster-mother, Tailtiu. The combination of Christian teachings and pagan holidays stemmed from the fact that a strong druidic impersonation had to be retained by the very first Irish Christian monks in order for them to assimilate themselves. The symbolic association of Jesus Christ to the Sun seemed to be a natural progression, as it had also been for for previously. In Irish mythology the god was the one who knew all the secrets of heaven and of earth and to whom, curiously, fidchell is attributed (the Gaelic equivalent of chess). Lugh’s astral symbol was the Sun and his weapon was a magical spear whose tip constantly reflected the image of the starry sky.

Ta’n tree cassyn or Triple Spiral

The ancient Celts believed in the continuing spiral of life symbolised by the Ta’n tree cassynTriskeles or Triple Spiral‘, yet marked the passing of time by observing the seasons. In addition to the four standard seasons that occur with the equinoxes and solstices, Celts also had festivals that marked the mid-points or actual beginnings of these seasons. Rather than discuss all eight periods, I will focus only on the seasons as we observe them in Western culture. However, it is also important to understand the significance of the festivals.


The dates of the four ancient traditional Irish holidays were interchanged:

  1. Imbolc marks the beginning of spring, a reminder of fertility and motherhood, onFebruary 1, about halfway between the winter solstice and the spring equinox. Spring or An tEarrach is composed of February, March, and April. 
  2. Beltane is the time of growth and renewal and is the second most important festival after Samhain, marking the beginning of the season of light onMay 1, about halfway between the spring equinox and summer solstice. Summer or An Samhraidh is composed of the months of May, June, and July.
  3. Lughnasad marks the end of summer and the beginning of fall, the beginning of the harvest season is a festival of thanksgiving for the bounty of the earth on August 1 approximately halfway between the summer solstice and autumn equinox. Autumn An Fómhar is composed of the months of August, September, and October.
  4. Samhain is the midpoint between the Fall equinox and the Winter solstice and begins on November 1. The festivities commence on the evening of October 31 is held on 1 November, but with celebrations beginning on the evening [when the Sun is at its lowest point in the heavens] of 31 October, as the Celt’s day began and ended at sunset. In the Celtic calendar An Geimhreadh or Winter, is composed of November, December, and January.

As you will note from above, the dates were chosen to be approximately consistent with the solstices and equinoxes; it did not matter that they coincided with them, since these points, in the latitude of Ireland, had little seasonal relevance for peasants and cattle ranchers. The feasts took place when the declination of the Sun was on average around 16° above or below the celestial equator. The switch to fixed dates was due as result of the Irish Church ratifying the use of the Julian calendar into common use, which was of course the one that had been officially adopted by the Church of Rome and regulated on the Sun; the traditional calendars based on the lunar count (synodic months, lunations), was not however, abandoned until very much later. For the Irish, the summer was from May 1 to November 1 and the winter from November 1 to May 1. As far as we know there was no spring or autumn as we would understand it today. So it is written in the Sanas Chormaic—“Cormac’s narrative.”

Lunation Cycle (the monthly cycle of relationship between the Sun and the Moon, as we experience it on earth)

Among the ancient Irish the fundamental astronomical directions, namely the meridian and equinoctial lines, were understood in a somewhat more complex way than that used by contemporary European populations. The term north was associated with the concept of low (old Irish: ichtar), while the South was coupled with the notion of “high” (old Irish: tuas) with evident reference to the lower and upper culmination of the stars. North was also associated with the left direction, the South with the right. This concept has been handed down over the centuries and even today in the languages of Celtic derivation the words that indicate North are the same ones that indicate the left side, and the same is true for South and the right side. 

To understand the meaning of this singular conception of orientation we must consider an observer facing east. The word of the ancient Irish language that indicates the generic east direction is t-air, whose etymological meaning is “(which stands) in front,” while the corresponding word which indicates the west is t-iar which literally means “(which stands ) behind.”  The stars rise in the east, in front (t-air) of the observer, then move southwards moving to his right and crossing “the clear half of the world” reserved for the living, as the ancient Irish texts define the sector of the sky. to the south. Once at the meridian, the stars culminate above, then begins the slow descent towards the western horizon which they reach at sunset, behind, that is, behind (t-iar), the observer. From this moment they move northwards declining towards the left side of the sky which ends at the bottom, at the lower culmination. The stars are now placed in correspondence with the “dark half of the world” in which, according to the aes sídhe Irish pagan texts, is where the kingdom of the dead, heroes, mythical beings and gods, was located. The Celtic ritual orientation system was such as to contrast a dark part (the North) with a bright one (the South) according to a dichotomy very dear to the druids.

The apparent motion of the stars was held in high regard by the Celts. Having to perform a ritual shift, they were careful to make it from left to right, that is, in the direction of the rotation of the celestial sphere; doing it in the opposite direction would have meant misfortune. The ancient Irish literature is very clear on this point, and even today those who go on pilgrimage to the remains of the monastery of Clonmacnoise, located in the centre of Ireland on the banks of the River Shannon, founded between 545 and 548 by the monk Ciarán mac an tSaeir (“son of the carpenter”), they must pray making three complete turns of the site in the direction of the apparent motion of the Sun. The rite of circumambulation concordant with the celestial sphere is also present in the Christian processions in Brittany.

The azimuth is the angle formed between a reference direction (in this example north) and a line from the observer to a point of interest projected on the same plane as the reference direction orthogonal to the zenith.

Returning to the guiding principle of the orientation of places of worship, we must note that the equinoctial direction could be correlated with the date of Easter which, as is known, is currently celebrated on the Sunday following the first full moon after the spring equinox. Therefore being a mobile date, the azimuth of the rising Sun at Easter could not be fixed in a determined manner. At that time the vernal equinox fell on March 18 of the Julian calendar (March 31 in the Gregorian calendar in 2021), and the Celtic Church celebrated Easter by calculating the Julian recurrence not through the Metonic cycle or enneadecaeteris devised by the mathematician Meton of Athens, as the Roman Church predicted, but with the cycle of the computist Anatolius of Laodicea and founder of the new Alexandrian computus paschalis, based on a period of 84 years for the recurrence of Easter dates. This cycle derived from the writings of Sulpicius Severus (ca. 363 – † ca. 425), whom in the first century AD lived in southern Gaul, approximately in the same areas where the Celtic Coligny calendar was developed. In this regard, it should be remembered that in 1983 Prof. Dáibhí Iarla Ó Cróinín RIA, of the University of Galway (Ireland), discovered in the Biblioteca Antoniana of Padua, MS I.27 a manuscript that written before the XI century and including extracts from previous manuscripts, on some sheets of which a panel reproducing the Easter cycle of Anatolius is copied, starting from the first half of the IV century AD 

Easter controversy

The controversy over the correct date for Easter began in Early Christianity as early as the II century AD. Discussion and disagreement over the best method of computing the date of Easter Sunday has been ongoing ever since and remain unresolved. Different Christian denominations continue to celebrate Easter on different dates, with Eastern and Western Christian churches being a notable example. The decision to make Easter a mobile feast sparked furious disputes within the Celtic Church in the III and IV centuries, nor were they appeased when they were told to adopt the adoption of a calculation algorithm known as the Cycle of Dionysius, from the name of Dionysius the Humble (Dionysius Exiguus), who in the fourth century prepared a table of 95 future dates of Easter (532–626), taking advantage of the fact that Easter repeats itself on the same date in the Julian calendar every 532 years. Only after AD 541 did a gradual acceptance of the method based on the Cycle of Dionysius within the Celtic Church begin to be used but suspiciously. In Southern Ireland it was not adopted until AD 630, but only after AD 703 throughout various other parts of Britain, AD 731 in other parts, in Scotland not until AD 716 and by the Welsh not until AD 768  some 52 years late. As I said people were suspicious of these new calculation and worried that it might lead them to celebrate easter at the wrong time.

The Hill of Tara (Teamhair or Cnoc na Teamhrach) near Skryne in County Meath, was the inauguration place and seat of the Ardrí na hÉireann (High King of Ireland). The archaeological finds on the hill, which is located in Co. Meath, show traces of the ancient settlements that made this a sanctuary (sacred space) from 2000 BC onwards. The structure located on the hill of Tara manifest significantly interesting astronomical alignments.

The chronology of important events and the counting of years and centuries were based on the method introduced by Dionysius the Little and ratified by the Council of Nicaea in 325, but also on traditional counts based on the start date of the world! As established in an ancient Irish text called Annála na gCeithre Máistrí (The Annals of the Four Masters); it is enough to consult the Annals of Ulster or the Annales Domus Fratrum de Multifernan to realise this: for many centuries, double or triple dates are reported. Ireland at the beginning of the V century was divided into four independent provinces and who constantly fought against each other: cóiceda Uladh (now Ulster) to the North, thuaidh cóiceda Laighean (North Leinster) to the East (with Tara as their capital, where the High king lived), cóiceda Mumhan (Munster) to the South and Irish cóiceda Chonnacht (Connacht) to the West; in the centre was a fifth small territory, Mide (Meath). Uladh (Ulster) was the first territory to be Christianised by St. Patrick as expressed by unidentified monks who compiled the precious chronicles known as the Annála Uladh (Annals of Ulster), ranging AD 431 to AD 1540.

Annals of the Four Masters, C iii 3, f.218v

The annals report not only the numerous wars between one province and another, listing in (bad) Latin and ancient Gaelic the vanquisher, the vanquished, the notable dead, but also the dates of settlement, death of bishops, abbots and saints, the fires of churches and monasteries, pestilences, famines, significant natural and astronomical phenomena. As for the chronology, it manifests itself as extremely singular. For example, at the beginning of the section relating to AD 460, the year of the death of Pope Leo I (Leo actually died on November 10, 461), we find: “Kl. Ienair 6 f., l. 23. Anno Domini .cccc.lx., .iiiimdclxiiii. — ‘U460.1 Leo Papa mortuus est, Romane Eclesie obtenuit sedem Petri .xxi. alias iiii.or annis & mense .i. & diebus .xiii., sicuti enumerat Beda in Cronico suo), in which we detect the calends of January (Kl. Ienair 6 f.), the age of the Moon corresponding to the 23rd day after the novilunio, the new moon (l. 23.), the dating according to Dionysius the Humble (Anno Domini.cccc.lx.,), that is, the year of Our Lord 460, and that according to the Annals of the Four Masters, is the year 4664 (iiiimdclxiiii) since the creation of the world. Note the unusual way of writing the number 4000 in Roman figures: not MMMM, but IIIIM; this way is typical of the Irish, who also wrote the Roman numerals with lowercase letters of their Celtic alphabet.

Sí an Bhrú – Newgrange built ca. 3200 BC

In the citations extracted from the Annals of Ulster we find frequent references to the chronicles of Bede the Venerable, an Anglo Benedictine monk who lived in Northumbria around the 6th-7th century, who wrote numerous works on astronomical subjects which were an important point of reference in the following six centuries. The calculation of the years of the Venerable Bede was one year different from that used by the Church of Rome, and in many passages at the beginning of the year the dating according to Bede is also reported. The reference to Bede the Venerable shows that the Annals of Ulster were compiled from 500-600 onwards and simultaneously extended backwards for a century. In the Annals of Ulster we find mentioned as many as 10 eclipses of the Sun, 12 of the Moon, 6 passages of comets and 6 northern lights. In the Annales Domus Fratrum de Multifernan, which were extended backwards in time up to the year 45, 6 solar eclipses, 8 lunar eclipses and 4 comet passages are recorded. The Irish monks who wrote the Annales carried out a very careful analysis of the Holy Scriptures with the aim of giving a chronological location to important events for Christianity. For example, in the year MF49.1 this curious quote is reported: “Ob. beata virgo Maria, anno vite sue lxiii”; Our Lady would therefore have died at the age of 63 in the year 49. The Annales report many other interesting facts, but what catches the eye is that these monks were true experts in calendars, systems of conversion between one calculation and another and methods of measuring time, as they knew how to skilfully extricate themselves in the complicated questions of ancient chronology.

Acknowledgements:

Cover Photograph:  To the Waters and the Wild, by Josh Mathews, featuring the night sky over Crocknaraw, on the Connemara coast, in Co Galway.