lawyer and patron of lawyers and judges. Sometimes called Ivo Helory or Ivo of Kermartin, he was born at Kermartin, near Tréguier (Brittany). His father, the lord of the manor, sent him to study canon law and theology at Paris for 10 years and then he studied civil law at Orléans under Peter de la Chapelle. As a student he was reputed to have practised monastic austerities of fasting and abstinence. On his return to Brittany in 1262 he was appointed by the archdeacon of Rennes as judge (‘official’) of the church courts.
Soon the bishop of Tréguier appointed him to the same office, in the exercise of which he won a reputation for complete impartiality, special care for poor litigants, and absolute incorruptibility. He repeatedly tried, often with success, to persuade litigants to settle out of court, thus avoiding expensive and sometimes unnecessary lawsuits.
Only in 1284 was he ordained priest and appointed parish priest of Tredrez. In 1287 he resigned his legal appointments and devoted himself to his parishioners, first at Tredrez and from 1292 at Lovannec. There he built a hospital where he tended the sick in person, and would give beggars his clothes or let them use his bed. Although he was no longer an official judge, he often acted as an unofficial arbitrator. Fluent in Latin and French as well as Breton, he was much in demand as a preacher outside his own neighbourhood. He died after an illness which lasted from the beginning of Lent to Ascensiontide. He was canonized in 1347. His cult is still popular in Brittany, where a ‘pardon’ festival, whose procession passes his tomb near Minihy, attracts many followers. Feast: 19 May.
AA.SS. Maii IV (1866), 538–614: A. de la Borderie, Monuments Originaux de l'Histoire de S. Yves (1887); Lives by C. de la Roncière (1925); A. Masseron, S. Yves d'après les témoins de sa vie (1952). See also B.L.S., v. 104–5; Bibl. SS., vii. 998–1002.