What was Saint Peter's missionary work?

From the earliest days of the Church, Peter was recognized as the Prince of the apostles and the first Supreme Pontiff; his see, Rome, has thus enjoyed the position of primacy over the entire Catholic Church.

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Catholic AnswerHis greatest achievement is that he was a follower of Our Blessed Lord, he did His Will, and was martyred for Him. Throughout The Bible, he was the leader of the little group of Apostles that Our Blessed Lord gathered around Himself. Our Blessed Lord gave him the keys of the kingdom, and guaranteed that He would be with him always. He is at all the greatest moments of Our Blessed Lord's life in the Gospels, and, of course, is named head of the Church and the first Pontiff.