Stephen of Penthièvre, Count of Tréguier, 3rd Lord of Richmond (1058/62 – 21 April 1136) was a Breton noble and a younger son of Odo, Count of Penthièvre[1] and Agnes of Cornouaille, sister of Hoël II, Duke of Brittany.
He is sometimes misidentified as "Stephen, Count of Brittany" in the court documents of King Henry I.
In 1110, he and his wife, Hawise, founded the Augustine Abbey of St Croix in Guingamp.
On an unknown date, he is recorded as having donated property to Rumbaugh Priory for the souls of his wife and children.
[2] Their children were: He died on 21 April 1136 and was buried in the Abbey of St Mary at York.