The phrase "vicar of Jesus Christ on earth" is a term often used to refer to the Pope. However, there are other synonyms that can be used to describe the leader of the Catholic Church. For example, he can also be referred to as the "Bishop of Rome," the "Holy Father," or simply as "Pope." Some other terms that have been used in the past include "Successor of Saint Peter," "Supreme Pontiff," and "Servant of the Servants of God." Regardless of the specific term used, the leader of the Catholic Church is considered to be the spiritual leader and representative of Jesus Christ on earth.