There are several people mentioned in the New Testament named James. The name "Jacob" is a Latinized version of Yakob - or Jacob, a very common Jewish name. Here, the person in question is the brother of Jesus. In order to distinguish him from the other people named James in the NT, the early Church gave him the moniker "the Just." Although the Church later argued that James was the son of Joseph through a marriage previous to Mary or that "brother" actually means "cousin" (owing to the belief that Mary was a perpetual virgin), the Bible gives no indication that he was not the natural son of Joseph and Mary, and the actual brother of the Lord Jesus.
Almost nothing is known of James' early life. He grew up in Nazareth, and at first apparently did not believe (Mark 3:31-35; John 7:5). After the death and resurrection of Jesus, James became a leader of the church in Jerusalem. Paul is reported to have met with James just after his conversion (Gal 1:18-20), and later Paul mentions James among the "pillars" of the church who "recognized the grace" of his call (Gal 2:9-10). James was also present at the Council of Jerusalem that decided Gentiles did not need to become Jews in order to follow Jesus (Acts 15:1-30). Finally, before Paul's arrest in Jerusalem, he met with James and "all the elders" (Acts 21:17-25). According to both Josephus and other early Church historians, James was martyred around A.D. 62 by being thrown from the "pinnacle of the Temple" and then stoned to death. He was said to have been buried and "his monument" was still present "by the temple" in the 4th century A.D.
In 2002 it was announced that an ossuary (bone box) had been found bearing the inscription, written in Aramaic, "James, son of Joseph, brother of Jesus." Although its authenticity has been challenged by some skeptics, experts have demonstrated that it is almost certainly authentic. Although the names "James (Yakob), "Joseph (Yoseph)," and "Jesus (Yeshua)" were very common in first century Judea, the specific combination written on the ossuary is unique, making the probability that it is indeed James' very high.