sentences:  Exactly what made this a betrayal ("proditio") in the eyes of the 10th century chronicler or those of Roger of Wendover, is unclear.It is unknown whether Osulf was also behind Eric's expulsion, despite being the main beneficiary, and whether he was expected to grant Eric safe passage and perhaps an escort to guide him safely through that part of Northumbria over which he (Osulf) had jurisdiction.It is equally obscure whether Maccus ambushed his victims, or was part of the escort, betraying them ("fraudulenter") as soon as he saw the opportunity.