Picture: Alphonse Hénaff · Public domain · Wikimedia Commons
Gurthiern
Welsh-born Breton saint
SaintPre-congregation
Feast: 3 July (not on the universal Roman calendar; kept in the Roman Martyrology or local calendars)
Born
450
Died
—
unknown
Beatified
—
not needed: before formal processes
Canonised
By tradition
recognised before formal processes began
Who they were
Gurthiern (also Guthiern, Gunthiern, and Gunthiernus) was a Welsh prince. According to the Vita sancta Gurthierni, he became a hermit in Brittany and founder of an abbey at Quimperlé. He is a Catholic and Orthodox saint with a feast day on 3 July.
Summary from Wikipedia (CC BY-SA 4.0), until this page is written up in full.
The miracles
Limited information available on this saint.
Why that counted as sanctity
Limited information available on this saint.