Between the third and fourth Centuries, the title of Pope was bestowed on bishops other than the head of the Church and sometimes on ordinary priests. The word comes from Latin papa (from the Gree pappas) meaning father.
The title has been exclusively reserved since the 9th Century for the Bishop of Rome. From the earliest times the Bishop of Rome's claim to the supreme headship of the Roman Catholic Church has been acknowledged by all within the fold. Among his other titles are Holy Father, Vicar of Christ and Pontifex Maximus, meaning chief bridge-builder.
Roman Catholics believe that the Pope is elected as the direct successor of the St. Peter to be the visible head of the Church on earth. By virtue of his position, he is the Church's supreme governor, judge and teacher.