Baithéne mac Brénaind

Baithéne mac Brénaind (also known as Saint Baoithin and Saint Buadán) was an Irish monk, one of Saint Columba's followers who accompanied him to Scotland around 563, and was the first successor as Abbot of Iona Abbey. The Annals of Tigernach record his birth in 534, and his death was likely between 596 and 598 according also to the Annals of Ulster. Irish genealogical records indicate him to be the "son of Brendan, son of Fergus, son of Conall Gulban, son of Niall Noígiallach", thus being a member of the Cenél Conaill branch of the Northern Uí Néill, as the abbots of Iona Abbey following the death of Columba often were.

Baithéne is still venerated in Ireland, but is most heavily associated with County Donegal where his cult was most active in Taughboyne and Culdaff. Celebrations of the saint in Donegal are ongoing, and a major celebration of the saint's 1400th death anniversary was celebrated in the parish of Taughboyne in 2000. Folklore about the saint from Donegal further refers to him using various variants of his name.

There is also evidence of Baithéne being venerated as Saint Bathan and Baodáin in Scotland as Abbey St Bathans in Berwickshire (south east Scotland) is named after him, as well as several other place names. Another place of his veneration in the Highlands and Islands before the Scottish Reformation was the now ruined 10th-century Celtic Church monastery and Christian pilgrimage site of at , which was dedicated to St Baithéne, as he is locally believed to have started the Christianisation of Strathglass and the holy well known as near Beauly in Glen Cannich.

The earliest source for Baithéne is Adomnán of Iona's Life of Columba (Vita Columbae), in which he is featured as Columba's close companion and successor. Two 12th-13th century lives of Baithéne also survive in the Codex Salmanticensis and Codex Insulensis but are heavily influenced by Adomnán's life.

Baithéne is recorded in the four major Irish martyrologies as sharing his feast day with Columba on 9 June.

Companion to Columba

Baithéne is heavily featured in Adomnán's Vita Columbae, where he is featured as Columba's trusted companion and chosen successor. He is called Columba's alumnus, which has variously been translated as 'foster-son' and 'disciple'. The list gives Baithéne an alternative name 'Conin' and it mentions that he had a brother called Cobthach.

Iona, Tiree, and Hinba

Baithéne's reign as abbot was fairly short as Columba died c. 597, and Baithéne's death is recorded as occurring c. 598, aged 66 according to the Annals of Clonmacnoise. No evident sources contemporaneous with Baithéne's abbacy survive.

Baithéne served as prior over a monastery connected to Iona on the island of Tiree. The name of the place where his monastery was located on Tiree was Mag Luinge or Campus Luinge. The monastery was a house for penitents from Iona. Some historians have thought that it may have supplied food to Iona.

In one story, Adomnán claimed that Columba went to Hinba and relaxed the penitential rules on one occasion. However, one monk named Neman refused to abide by the relaxation. Columba rebuked him and said 'Neman, Baithéne and I have allowed a relaxation in the diet and you refuse it. But the time will come when in the company of thieves in the forest you will eat the flesh of a stolen mare'. This monk eventually left the monastery and went back into the world, and one day found himself among thieves eating such meat.