Who was James in Acts of the Apostles?

There are three James' mentioned in Acts.

13And when they were come in, they went up into an upper room, where abode both Peter, and James, and John, and Andrew, Philip, and Thomas, Bartholomew, and Matthew, James the son of Alphaeus, and Simon Zelotes, and Judas the brother of James. 14These all continued with one accord in prayer and supplication, with the women, and Mary the mother of Jesus, and with his brethren.

The first was James the brother of John, both fisherman and disciples and Apostles. The second was James the son of Alphaeus, sometimes referred to as James the less. The third was James the half-brother of Jesus, who finally came to believe after the resurrection and then rose to a place of leadership in the early church. He presided over the first church council in Jerusalem in Acts 15.