Finan was an Irish monk of Iona, who succeeded St Aidan (q.v.) as Bishop of Lindisfarne in AD 651 and carried on his missionary work successfully south of the Humber. In particular he baptised the king of Mercia, Peada, son of the obstinately heathen Penda, as well as Sigenert, the king of the East Saxons, sending Diuma and St Cedd to spread the faith in Mercia and Essex. St Finan upheld the Celtic dating of Easter and strongly resisted those from Kent or abroad, who were to him innovators in this matter.