He took the religious habit in the convent of N.-D. de Bonne Nouvelle at Morlaix (1483). After completing his studies at Nantes, in 1489 he was sent to Rennes. There the Duchess Anne of Brittany chose him as her confessor and wished him to accompany her to the court of France when she married Charles VIII (1491) and later Louis XII (1498), both of whom became his penitents. On the king’s proposal, he was made prior of St Maximin in Provence in 1504, which he governed through a vicar, and at the queen’s suggestion was elected bishop of Rennes (29 Jan. 1507).
Brittany owes largely to Mayeug its union with the French crown. But his name is especially linked to his great charity towards his neighbour, which he was able to exercise first as court confessor and almoner and then during his long episcopate. Numerous miracles took place at his tomb; a beginning was made in 1637 towards the introduction of his cause of beatification.