He was a sixth-century priest, uncle to Saint Herve.

Rivoare is called "the first emigrant priest on the continent".

The Latin term which designates it -- "antistes" -- implies an ecclesiastic power.

Only after his arrival in Armorica would monasteries and bishoprics be established.

The previous bishops or abbots who evangelized the region were often designated as itinerant, coming from the British Isles without being fixed on the continent.