Saint Peter
Peter was also known as Simon or Cephas. He was the brother of Andrew. He became the leading Apostle after Pentecost until the Council of Jerusalem in 50 A.D. Afterward his whereabouts are not known with certainty.
Peter was crucified in Rome under Nero. An ancient historian records that he asked to be crucified upside down because he felt unworthy to be crucified as his Lord.
In artistic renderings St. Peter's primary attribute is the key to heaven, referring to Christ's words to Peter in Matthew 16:18-19. "I will give to thee the keys of the kingdom of heaven."
He also often has a book, a reference to the two New Testament letters ascribed to him.