From The Stargate Omnipedia
Member of a religious order in the village of Camelot. Antonius, the town's historian, used Abelard as an alibi, telling his wife Livia that he would be reviewing council minutes with Brother Abelard. In truth, Antonius went to admit SG-1 into Merlin's library.
Camelot - Antonius tells his wife he is going to work with Abelard, but instead gives SG-1 access to Merlin's library.