Editing Celtic Christianity (section)

==Pan-Celtic traditions==
Caitlin Corning identifies four customs that were common to both the Irish and British churches but not used elsewhere in the Christian world.<ref>{{harvnb|Corning|2006|pp=1–19}}</ref>

===Easter calculation===
{{main article|Easter controversy|computus}}{{anchor|Computus}}
[[Easter]] was originally dated according to [[Hebrew calendar]], which [[Hebrew calendar#New year|tried to place Passover]] on the first full moon following the [[Spring equinox (Northern Hemisphere)|Spring equinox]] but did not always succeed. In his ''[[Life of Constantine]]'', [[Eusebius]] records that the [[First Council of Nicaea]] (325) decided that all Christians should observe a common date for Easter separate from the Jewish calculations, according to the practice of the [[bishops of Rome]] and [[bishop of Alexandria|Alexandria]].<ref name=conlet>{{Citation| author  = Constantine| author-link = Constantine the Great| chapter = Letter on the Keeping of Easter to those not present at Nicaea| date = 325| editor  = Eusebius of Caesaria| editor-link = Eusebius of Caesaria| title  = The Life of Constantine| volume = III| publisher = Signature Books| at = §18–20| publication-date = 1996| isbn = 1-56085-072-8|chapter-url=http://www.ccel.org/ccel/schaff/npnf214.vii.x.html}}</ref> Calculating the proper date of Easter (''computus'') then became a complicated process involving a [[lunisolar calendar]], finding the first Sunday after an idealized Passover on the first full moon after the equinox.

Various tables were drawn up, aiming to produce the necessary alignment between the [[solar year]] and the [[moon phases|phases]] of the [[ecclesiastical full moon|calendrical moon]]. The less exact [[octaeteris|8-year cycle]] was replaced by (or by the time of) [[Augustalis (bishop)|Augustalis]]'s treatise "[[De ratione Paschae|On the measurement of Easter]]", which includes an 84-year cycle based on [[Metonic cycle|Meton]]. This was introduced to Britain, whose clerics at some point modified it to use the [[Julian calendar]]'s original equinox on 25 March instead of the Nicaean equinox, which had already drifted to 21 March. This calendar was conserved by the Britons and Irish<ref>{{harvnb|Wormald|2006|p=224 n. 1}}</ref> while the Romans and French began to use the [[Victorius of Aquitaine|Victorian]] cycle of 532 years. The Romans (but not the French) then adopted the still-better work of [[Dionysius Exiguus|Dionysius]] in 525, which brought them into harmony with the [[Church of Alexandria]].

In the early 600s Christians in Ireland and Britain became aware of the divergence in dating between them and those in Europe. The first clash came in 602 when a synod of French bishops opposed the practices of the monasteries established by [[Columbanus|St&nbsp;Columbanus]]; Columbanus appealed to Pope Gregory I but received no answer and finally moved from their jurisdiction. It was a primary concern for St&nbsp;Augustine and his mission, although [[Oswald of Northumbria|Oswald]]'s flight to [[Dál Riata]] and eventual restoration to his throne meant that Celtic practice was introduced to [[Northumbria]] until the 664 [[Synod of Whitby|synod in Whitby]]. The groups furthest away from the [[Gregorian mission]] were generally the readiest to acknowledge the superiority of the new tables: the bishops of southern Ireland adopted the continental system at the [[Synod of Mag Léne]] ({{circa|lk=no|630}}); the {{circa|lk=no|697}} [[Council of Birr]] saw the northern Irish bishops follow suit. The [[Iona Abbey|abbey at Iona]] and its satellites held out until 716,<ref>{{harvnb|John|2000|p=34}}</ref> while the Welsh did not adopt the Roman and Saxon ''computus'' until induced to do so around 768 by Elfodd, "archbishop" of Bangor.

===Monastic tonsure===
[[File:Fra Angelico 052.jpg|left|thumb|The Roman [[tonsure]], in the shape of a crown, differing from the Irish tradition, which is unclear but involved shaving the hair from ear to ear in some fashion]]
All monks of the period, and apparently most or all clergy, kept a distinct [[tonsure]], or method of cutting one's hair, to distinguish their social identity as men of the cloth. In Ireland men otherwise wore longish hair, and a shaved head was worn by [[Slavery in the Early Middle Ages|slave]]s.<ref>{{harvnb|Ryan|1931|p=217}}</ref>

The prevailing Roman custom was to shave a circle at the top of the head, leaving a halo of hair or ''corona''; this was eventually associated with the imagery of Christ's [[crown of thorns]].<ref>{{harvnb|McCarthy|2003|p=146}}</ref> The early material referring to the Celtic tonsure emphasizes its distinctiveness from the Roman alternative and invariably connects its use to the Celtic dating of Easter.<ref>{{harvnb|McCarthy|2003|p=140}}</ref> Those preferring the Roman tonsure considered the Celtic custom extremely unorthodox, and associated it with the form of tonsure worn by the [[heresiarch]] [[Simon Magus]].<ref>{{harvnb|McCarthy|2003|pp=141–143}}</ref> This association appears in a 672 letter from Saint [[Aldhelm]] to King [[Geraint of Dumnonia]], but it may have been circulating since the Synod of Whitby.<ref name=McCarthy141>{{harvnb|McCarthy|2003|p=141}}</ref> The tonsure is also mentioned in a passage, probably of the 7th century but attributed wrongly to Gildas: "''Britones toti mundo contrarii, moribus Romanis inimici, non solum in missa sed in tonsura etiam''" ("Britons are contrary to the whole world, enemies of Roman customs, not only in the Mass but also in regard to the tonsure").<ref>A. W. Haddan and W. Stubbs (ed.), ''Councils and Ecclesiastical Documents Relating to Great Britain and Ireland'', 3 vols (Oxford, 1869–78), I, 112-3</ref>

The exact shape of the Irish tonsure is unclear from the early sources, although they agree that the hair was in some way shorn over the head from ear to ear.<ref name="McCarthy">{{harvnb|McCarthy|2003|pp=140–167}}</ref> In 1639 [[James Ussher]] suggested a semi-circular shape, rounded in the front and culminating at a line between the ears.<ref>{{harvnb|McCarthy|2003|pp=147–148}}</ref> This suggestion was accepted by many subsequent writers, but in 1703 [[Jean Mabillon]] put forth a new hypothesis, claiming that the entire forehead was shaven back to the ears. Mabillon's version was widely accepted, but contradicts the early sources.<ref name="McCarthy149">{{harvnb|McCarthy|2003|p=149}}</ref> In 2003 Daniel McCarthy suggested a triangular shape, with one side between the ears and a vertex towards the front of the head.<ref name="McCarthy"/> The ''[[Collectio canonum Hibernensis]]'' cites the authority of Saint Patrick as indicating that the custom originated with the swineherd of [[Lóegaire mac Néill]], the king who opposed Patrick.<ref>{{harvnb|McCarthy|2003|pp=142–143}}</ref>

===Penitentials===
{{main article|Penitential}}
In Christian Ireland – as well as Pictish and English peoples they Christianised – a distinctive form of [[Sacrament of Penance (Catholic Church)|penance]] developed, where confession was made privately to a priest, under the seal of secrecy, and where penance was given privately and ordinarily performed privately as well.<ref>{{harvnb|McNeill|Gamer|1938|p=28}}</ref> Certain handbooks were made, called "penitentials", designed as a guide for confessors and as a means of regularising the penance given for each particular sin.

In antiquity, penance had been a public ritual. Penitents were divided into a separate part of the church during liturgical worship, and they came to Mass wearing [[sackcloth]] and ashes in a process known as ''exomologesis'' that often involved some form of general confession.<ref>{{harvnb|McNeill|Gamer|1938|pp=7–9}}</ref> There is evidence that this public penance was preceded by a private confession to a bishop or priest (''sacerdos''), and it seems that, for some sins, private penance was allowed instead.<ref>{{harvnb|McNeill|Gamer|1938|pp=9–12}}</ref> Nonetheless, penance and reconciliation was prevailingly a public rite (sometimes unrepeatable), which included [[absolution]] at its conclusion.<ref>{{harvnb|McNeill|Gamer|1938|pp=13–17}}</ref>

The Irish penitential practice spread throughout the continent, where the form of public penance had fallen into disuse. Saint Columbanus was credited with introducing the ''medicamenta paentitentiae'', the "medicines of penance", to Gaul at a time when they had come to be neglected.<ref>{{harvnb|Brown|2003|p=252}}</ref> Though the process met some resistance, by 1215 the practice had become established as the norm, with the Fourth Lateran Council establishing a canonical statute requiring confession at a minimum of once per year.

===Peregrinatio===
A final distinctive tradition common across Britain and Ireland was the popularity of ''peregrinatio pro Christo'' ("exile for Christ"). The term ''peregrinatio'' is [[Latin]], and referred to the state of living or sojourning away from one's homeland in Roman law. It was later used by the [[Church Fathers]], in particular Saint [[Augustine of Hippo]], who wrote that Christians should live a life of ''peregrinatio'' in the present world while awaiting the [[Kingdom of God]]. Augustine's version of ''peregrinatio'' spread widely throughout the Christian church, but it took two additional unique meanings in Celtic countries.<ref name=Corningperegrinatio>{{harvnb|Corning|2006|p=17}}</ref>

In the first sense, the penitentials prescribed permanent or temporary ''peregrinatio'' as penance for certain infractions. Additionally, there was a tradition of undertaking a voluntary ''peregrinatio pro Christo'', in which individuals permanently left their homes and put themselves entirely in God's hands. In the Irish tradition there were two types of such ''peregrinatio'', the "lesser" peregrinatio, involving leaving one's home area but not the island, and the "superior" peregrinatio, which meant leaving Ireland for good. This voluntary exile to spend one's life in a foreign land far from friends and family came to be termed the "white martyrdom".<ref name=woods>{{cite journal |url=http://www.spiritualitytoday.org/spir2day/853735woods.html#3 |last=Woods |first=Richard |title=The Spirituality of the Celtic Church |journal=Spirituality Today |date=Fall 1985 |volume=37 |issue=3 |pages=243–255 |archive-url=https://web.archive.org/web/20131103040938/http://www.spiritualitytoday.org/spir2day/853735woods.html#3 |archive-date=3 November 2013 }}</ref>

Most ''peregrini'' or exiles of this type were seeking personal spiritual fulfilment, but many became involved in missionary endeavours. The Briton Saint Patrick became the evangelist of Ireland during what he called his ''peregrinatio'' there, while [[Samson of Dol|Saint Samson]] left his home to ultimately become bishop in Brittany. The Irishmen [[Columba]] and Columbanus similarly founded highly important religious communities after leaving their homes.<ref name=Corningperegrinatio/> Irish-educated English Christians such as Gerald of Mayo, the [[Two Ewalds]], [[Willehad]], [[Willibrord]], [[Wilfrid]], [[Ceolfrith]], and other English all followed these Irish traditions.