 Æthelbert sent out missionaries to the pagans of Northern Europe , among them <unk> and <unk> , who went to northern Germany . <unk> 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 " <unk> " , 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 . 
