At the commencement of the battle, Bede tells us that the pagan Æthelfrith slaughtered 1200 monks from the important monastery of Bangor-on-Dee in Maelor because, he said, "they fight against us, because they oppose us by their prayers".
Beda cóntanos que ao principio da batalla o pagán Æthelfrith matou 1200 monxes do mosteiro de Balor-Is-Coed (Balor do bosque baixo) porque, como dixo, loitan contra nós cos seus rezos.