The Twelve are arranged in three groups of 4 each. He is always listed first in the lists. We also know more about Peter than the other 12. Peter was brought to Christ by his brother, Andrew, who also became one of the 12. The family was in the fish business.
Tradition says they marketed sun-dried fish in Jerusalem.
Peter was from Bethsaida but also lived in Capernaum. He wrote the two Epistles which bare his name, and may have had much input into Mark's gospel, as he was a close friend to John Mark. He was the spokesman for the 12, and one of the inner circle. Peter is the first Apostle to associate with the gentile mission, though he was largely an apostle to his own people. He was imprisoned for his faith, and upon his release he traveled outside of Palestine.