The Pope is the leader of the worldwide Catholic Church and the Bishop of Rome. He rules the smallest state in the world - Stato della Cittą del Vaticano ('Vatican City State' - the Vatican City). The name of the city/state comes from the Vatican Hill on which it is built.
The reigning Pope took a hand (by messengers) in Arthur's affairs, as in the affairs of other kings, often enough that he must be recognized both as a force and as a character - or perhaps, since Pope follows Pope as more than one character - in the Arthurian saga.
It was also the Pope who ordered Arthur to be reconciled with his wife after Lancelot rescued her from the stake, the Pope's command reaching them while Arthur besieged them in Joyous Garde.
Arthur met the current pontiff in person when he conquered Rome and
was crowned emperor by the pope's hand, with all the royalty that could be made, and sojourned [in Rome] a time.
Bertholai | The Legend of King Arthur
Dionido | The Legend of King Arthur
Elutherius | The Legend of King Arthur
Genievre | The Legend of King Arthur
Gregorio | The Legend of King Arthur
Saint Peter | The Legend of King Arthur
Romanus | The Legend of King Arthur
Turinoro | The Legend of King Arthur