Wikipedia
Dymphna
Saint Dymphna (also: Dympna, Dimpna, ' Damhnait', ' Damnat', from Gaelic Damh=stag and ait=little, i.e. "fawn".) (pronounced "Dimf-nah") is a Christian saint. According to tradition, she lived in the 7th century and was the daughter of a pagan Irish king and his Christian wife. She was murdered by her father.
The story of Saint Dymphna was first recorded in the 13th century by a canon of the Church of St. Aubert at Cambrai, France. It was commissioned by Guiard of Laon (1238–1248), the Bishop of Cambrai.
The author expressly stated that his work was based upon a long-standing oral tradition and a persuasive history of miraculous healings of the mentally ill.