The leader of the Catholic Church in a kingdom or in general is the Pope. The Pope is the Bishop of Rome and is considered the visible head of the worldwide Catholic Church. He holds the highest office in the Church, known as the papacy, and is regarded as the successor of Saint Peter, who is traditionally recognized as the first leader of the Church
. The Pope exercises supreme, full, immediate, and universal power over the entire Catholic Church, a doctrine known as papal supremacy. This means he has authority over all bishops and the faithful, and his leadership is often compared to that of a king ruling a country. The Pope is also the head of state for Vatican City, the sovereign territory of the Holy See
. Historically, the Pope has been recognized as the spiritual leader of Catholics in kingdoms and states, sometimes with significant influence over temporal rulers. However, the Pope's authority is primarily spiritual and ecclesiastical rather than political, although there have been periods when popes wielded considerable political power
. In summary, the leader of the Catholic Church in a kingdom is the Pope, who serves as the supreme pontiff and spiritual head of the Church worldwide
