Æthelbert sent out missionaries to the pagans of Northern Europe, among them Alubert and Liudger, who went to northern Germany. Liudger had earlier been a pupil at the school in York, and went on to become the first Bishop of Munster. Æthelbert was the recipient of letters from one of the missionaries – Lull, the Archbishop of Mainz, assuming that Lull's correspondent "Coena", who is an archbishop and who was being asked for the works of Bede, is actually Æthelbert, as most historians seem convinced of. Books were sent to the missionaries from the York library.