Archbishop Asterius of Milan consecrated Birinus as a bishop. Birinus arrived in southern Britain . He had planned to go to the midlands of England to preach there. But when he found the Gewisse in Wessex were completely pagan, he decided to stay with them. He began to convert the Gewisse (West Saxons) to Christianity. In 635 King Cynegils of Wessex was baptized by Birinus and King Oswald of Northumbria agreed to be his Godfather. This may have been a condition of the marriage between Oswald and Cynegils's daughter, Cyneburh. He gave Bishop Birinus the city of Dorchester and several churches so he could convert the pagans in Wessex. 