Pentecost is the celebration of the person of the Holy Spirit coming upon the Apostles, Mary, and the first followers of Jesus, who were gathered together in the upper room.

As early as the mid-third century, there was evidence of the tradition to honour these two saints together. Peter (originally named Simon), a humble Galilean fisher, was on of the 12 apostles and was called by Jesus to "feed my sheep" as the Church's first pope. Paul (originally named Saul) had a miraculous encounter with the risen Jesus that led to his dramatic conversion, and he would become "Apostle of the Gentiles" and author of many New Testament letters.

Learn more at https://www.catholicnewsagency.com/saint/sts-peter-and-paul-501