From the Treasury of Daily Prayer:

St. James of Jerusalem (or “James the Just”) is referred to by St. Paul as “the Lord’s brother” (Galatians 1:19). Some modern theologians believe that James was a son of Joseph and Mary and, therefore, a biological brother of Jesus. But throughout most of the Church (historically, and even today), Paul’s term “brother” is understood as “cousin” or “kinsman,” and James is though to be the son of a sister of Joseph or Mary who was widowed and had come to live with them. Along with other relatives of our Lord (except His mother), James did not believe in Jesus until after His resurrection (John 7:3-5; 1 Corinthians 15:7). After becoming a Christian, James was elevated to a position of leadership within the earliest Christian community. Especially following St. Peter’s departure from Jerusalem, James was recognized as the bishop of the Church in that holy city (Acts 12:17; 15:12ff). According to the historian Josephus, James was martyred in AD 62 by being stoned to death by the Sadducees. James authored the Epistle in the New Testament that bears his name. In it, he exhorts his readers to remain steadfast in the one true faith, even in the face of suffering and temptation, and to live by faith the life that is in Christ Jesus. Such a faith, he makes clear, is a busy and active thing, which never ceases to do good, to confess the Gospel by words and actions, and to stake its life, both now and forever, in the cross.