Snorri Sturluson,
Heimskringla — Magnus Erlingson's Saga
“ Erling replied to them thus: -- "It is probable that we and Earl Sigurd shall soon meet. There are also many men in this band whose handy-work remains in our memories; such as cutting down King Inge, and so many more of our friends, that it would take long to reckon them up. These deeds they did by the power of Satan, by witchcraft, and by villainy; for it stands in our laws and country rights, that however highly a man may have been guilty, it shall be called villainy and cowardly murder to kill him in the night. ”
