According to the Golden Legend, St Ursula, daughter of the King of Brittany, married Conon, son of the King of England and after a pilgrimage to Rome with eleven thousand virgins arrived at Cologne where they were all killed by the Huns. On the reverse of the panel (see below) are St Hugh of Lincoln with a swan and St Bruno with an olive branch. This is the work of a different artist from the front. Hugh of Lincoln was the Carthusian monk whose pet swan predicted his death by refusing to eat. St Bruno, founder of the Carthusian Order, refused a bishopric, hence the discarded mitre and crozier. He was compared to an olive branch, able to bear fruit even in difficult soil. The saints indicate that the altarpiece was a Carthusian commission.