Pope

Pope (i.e. Papa), a title originally given to all bishops of the Church, and eventually appropriated by Leo the Great, the bishop of Rome, as the supreme pontiff in 449, a claim which in 1054 created the Great Schism, and which asserted itself territorially as well as spiritually, till now at length the Pope has been compelled to resign all territorial power. The present Pope, Pius X., is the successor of 258 who occupied before him the Chair of St. Peter.

Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)