Migrated to Cesambre, a small island near Aleth in Armorica, Brittany (in modern France) to live as a hermit; the island was accessible only at low tide, and for centuries was known as Aaron in his honour. His reputation attracted spiritual students, including Saint Malo. The students formed a monastery, and Aaron lived there as a monk, and served as their abbot.
- Book of Saints, by the Monks of Ramsgate
- Dictionary of Saints, by John Delaney
- Lives of the Saints by Father Alban Butler
- Our Sunday Visitor’s Encyclopedia of Saints
- “Saint Aaron of Brettany“. Saints.SQPN.com. 25 June 2013. Web. 11 December 2013. <>