St. Simon is a relative of Jesus’, possibly a first cousin. He is mentioned in the Gospel of Matthew, and is listed as one of the brethren of Christ in Acts, present at the birth of the Church on the first Pentecost.
Simon was also reported to be at the martyrdom of St. James the Lesser, and was chosen to succeed James as the bishop of Jerusalem. In the year 66, before the city fell to the Romans, Christians received a divine warning. Simon led them to relocate at nearby Pella.
After Jerusalem was destroyed, Simon led the Christians back to the city. Under his leadership, they performed miracles and converted many.
St. Simon was eventually arrested and tortured for being Jewish and a Christian. He was crucified and died a martyr for the Church.