For ten points, name this ecclesiastical office whose holder is the head of the Catholic Church.
Holders of this office were heavily influenced by Theodora and her daughter Marozia during the Pornocracy. The son of one man with this title hosted the lewd Banquet of Chestnuts and was the sister of Lucrezia. Another man who held this position feuded with (*) Philip IV, and his successor moved the seat of this position to Avignon. The Council of Constance resolved the issue of who held this post and thus ended the Western Schism. The infallibility of people in this post when speaking ex cathedra was decreed by Pius IX. For ten points, name this ecclesiastical office whose holder is the head of the Catholic Church.
Holders of this office were heavily influenced by Theodora and her daughter Marozia during the Pornocracy.
Pope [accept Papacy; accept Bishop of Rome] &lt;BZ&gt;