Very little is known about Brioc's early life, as his 9th century "" is not altogether reliable. It states that he came from Ceredigion where, indeed, he has a church at Llandyfriog. He received his education in Ireland and then studied under Germanus of Auxerre. He is believed to have spent time at Rothesay on the Isle of Bute in Scotland, where a church was dedicated to him and his name was commemorated in the annual St. Bruix Fair. He most likely returned to France early in 431, accompanied by Saint Illtud.