 On Sunday, May 25, 1941, ground was broken for Mount St. Peter Church. The event was celebrated by the priests of St. Peter's congregation and about two thousand people showed up to watch. The cornerstone was blessed on Sunday, September 7, 1941, by Reverend Alfred Koch, who was the Arch Abbot of St. Vincent in Latrobe, Pennsylvania. Many other priests from the area were also present. Father Paul Tomlinson of St. Peter's Church in Pittsburgh delivered the sermon in English and Archabbot Koch closed the ceremony with the Pontifical Benediction in Italian. The large red cornerstone was made of granite and was fitted with an iron box. The box contained the memorial reports of the congregation, newspapers, American and Papal coins, and medals of the church. The cornerstone was placed so that it can be seen from inside the church. It is located by the altar of the Sacred Heart.
