Three men named James stand in the apostolic record and the West has spent most of its history with two of them. James son of Zebedee is never confused with anyone: he is John's brother, one of the inner three, and Agrippa kills him in Acts 12. The trouble is the other two. James son of Alphaeus is one of the Twelve and is named in all four apostle lists and nowhere else. James the Just is the brother of the Lord, presides at the Council of Jerusalem, writes the epistle and is the first bishop of Jerusalem — and is never called one of the Twelve. Jerome, arguing against Helvidius that Mary bore no other children, identified the brother of the Lord as a cousin and folded him into the son of Alphaeus, and the Latin West has largely read them as one man since. The East never made the identification and keeps them apart, counting James the Just among the Seventy rather than the Twelve. This dataset follows the East and keeps three persons, which is why James son of Alphaeus has almost nothing on his page: strip out what belongs to James the Just and four apostle lists are what remains.
De Viris Illustribus