Antonius was the village historian in Camelot. He was killed by the black knight in Episode 9.20 "Camelot".
Antonius was the village historian of Camelot. He and Camelot's leader, Meurik, greeted SG-1 warmly when they arrived at the village pub. They happily discussed King Arthur and scoffed that the king was mortally wounded at Camlann.
After Meurik departed when Daniel Jackson brought up Merlin, Antonius explained that most villagers believed Merlin was a wizard of mischief and most dared not speak his name. Antonius further explained that Merlin's library had been locked up since he disappeared, and that no one was allowed to enter it: "The library is protected by a powerful curse. It is said that all those who enter Merlin's sanctuary forfeit their lives to its guardian, the Black Knight."
After a girl, Valencia, and her younger brother Ramus showed Daniel and Cameron where the library was, the children explained that only the key could open the door. Daniel tried, but a forcefield of some sort shocked him. Valencia explained the key was kept in the village archives, which were run by Antonius.
Daniel followed Antonius around the Camelot market, appealing to his love of history and explaining that they had defeated a Black Knight on their world already, which revealed treasures and knowledge that led his team here to Camelot. Daniel's entreaties worked, and Antonius helped SG-1 break into the library under cover of darkness. He forbade them to tell anyone of his assistance, not Meurik, and most certainly not his wife, who believed he was reviewing council minutes with Brother Abelard. All of them looked around at the numerous dusty books that furnished the library.
When SG-1 uncovered a hidden chamber within the library, Antonius decided to leave, stating they had tempted fate enough. He returned to home, carrying one of Merlin's books. Finding his bedroom empty, he called to his wife, Livia. In the meantime, SG-1 were investigating an Ancient Control panel within the hidden chamber. When they drew close, they activated a proximity alert and Merlin's safeguards, namely the holographic Black Knight. The Black Knight appeared in Antonius's room and murdered the historian.
Livia apparently found the body; her screams echoed throughout the town and brought SG-1 running. The volume from Merlin's library was found with Antonius's body, and Meurik accused SG-1 of entering Merlin's library, thus bringing forth the Curse of the Black Knight
--Aurora 18:04, 21 June 2006 (PDT)