The title of Vicar of Christ implies that Jesus Christ delegated to him His own jurisdiction over the Church. A vicar is one who exercises the authority vested in the principal by delegation from him. A viceroy or vice-king governs a subordinate kingdom, __vice regis__, in place of the king. A vicar-general exercises episcopal jurisdiction, __vice episcopi__, in place of the bishop, and governs the diocese during his absence. So when St. Peter is said to have been made by our Lord His Vicar, it means that he received jurisdiction to govern in the place of Jesus Christ Himself, Who is by personal and inherent right the High Priest of the Catholic Church, but Who, being absent from the earth, must exercise His functions by a substitute. It is unquestionable that, under the Old Law, the high-priest was the vice gerent of God, and the supreme head of the Jewish Church. It is equally unquestionable that, in establishing the New Law, Christ appointed St. Peter His Vicar and the Supreme Head of the Christian Church. There is nothing clearer in the New Testament than this. Jesus Christ distinctly promised to St. Peter that He would build His Church upon him, and would give him the keys of the kingdom of heaven; and He actually fulfilled these promises before He ascended into heaven, by committing His universal flock to him alone to feed and rule it. This promise is recorded in the sixteenth chapter of St. Matthew's Gospel: {202} "Jesus saith to them: But whom do you say that I am? Simon Peter answered and said: Thou art Christ the Son of the living God. And Jesus answering, said to him: Blessed art thou, Simon Bar-Jona: because flesh and blood hath not revealed it unto thee, but My Father who is in heaven. And I say to thee: That them art Peter; and upon this rock I will build My Church, and the gates of hell shall not prevail against it. And I will give to thee the keys of the kingdom of heaven. And whatsoever thou shalt bind upon earth, it shall be bound also in heaven; and whatsoever thou shalt loose on earth, it shall be loosed also in heaven." In this magnificent promise, Jesus Christ evidently declares His intention to delegate supreme power to St. Peter, and constitute him His Vicar in the Christian Church.