The pope is the Bishop of Rome and therefore ex officio
the leader of the worldwide Catholic Church.
The primacy of the Roman bishop is largely derived
from his role as the supposed apostolic successor to Saint Peter,
to whom Jesus is said to have given the Keys of Heaven
and the powers of "binding and loosing",
naming him as the "rock" upon which the church would be built.
Since the 1860s, the pope has also been head of state of Vatican City,
a sovereign city-state entirely enclaved within Rome.
The current pope is Francis, who was elected on 13 March 2013