(from the http://www.bibleinfo.com/en/questions/who-were-twelve-disciples webpage)
Simon Peter, son of Jonas, was a fisherman who lived in Bethsaida and Capernaum. He did evangelistic and missionary work among the Jews, going as far as Babylon. He was a member of the Inner Circle and authored the two New Testament epistles which bear his name. Tradition says he was crucified, head downward, in Rome.
In every apostolic list, the name Peter is mentioned first. However, Peter had other names. At the time of Christ, the common language was Greek and the family language was Hebrew. So his Greek name was Simon (Mark 1:16; John 1:40, 41). His Hebrew name was Cephas (1 Corinthians 1:12; 3:22; 9:5 and Galatians 2:9). The Greek meaning of Simon is rock. The Arabic meaning of Cephas is also rock.
By trade, Peter was a fisherman. He was a married man (1Corinthians 9:5) and his home was Capernaum. Jesus probably made His headquarters there when He visited Capernaum. Peter was also a Galilean as was typical of many of the other disciples. Josephus described the Galileans this way, "They were ever fond of innovation and by nature disposed to change and delighted in sedition. They were ever ready to follow the leader and to begin an insurrection. They were quick in temper and given to quarreling and they were very chivalrous men." The Talmud says this of the Galileans, "They were more anxious for honor than for gain, quick-tempered, impulsive, emotional, easily aroused by an appeal to adventure, loyal to the end." Peter was a typical Galilean. Among the twelve, Peter was the leader. He stands out as a spokesman for all the Apostles. It is he who asked the meaning of the difficult saying in Matthew 15:15. It is he who asked how often he must forgive. It is he who inquired about the reward for all of those who follow Jesus. It is he who first confessed Jesus and declared Him as the Son of the Living God. It is he who was at the Mount of Transfiguration. It is he who saw Jairus' daughter raised to life. Yet, it is he who denied Christ before a maiden. He was an Apostle and a missionary who laid down his life for his Lord. It is true, Peter had many faults, but he had always the saving grace of the loving heart. No matter how many times he had fallen and failed, he always recovered his courage and integrity.
Peter was martyred on a cross. Peter requested that he might be crucified head downward for he was not worthy to die as his Lord had died. His apostolic symbol is a cross upside down with crossed keys.