During the sixth century, some of the most significant names in the history of Irish Christianity studied at the Clonard monastery.

He emerges from early Irish writings as a man of generous hospitality with a reputation for sanctity and spirituality who was an intuitive judge of character.

This is evidenced both in his title ('Prophet of Ireland'), and by his attendance at the synod of Meltown, in which Columba was brought to trial over his role in the Battle of Cúl Dreimhne in 561.

[4] His friendship and support for Columba resulted in important connections between Birr and the Columban foundations.

Brendan's monastery at Birr was later to produce the MacRegol Gospels, which are now housed at the Bodleian Library in Oxford.