The words have the character of a brief marginal gloss, later incorporated innocently into the text. Josephus probably wrote of the death of a Jewish Jerusalem leader called James, and a Christian reader thought the reference must be to James the brother of the Lord who, according to Christian tradition, led the Jerusalem Chruch about the time in question. This reader accordingly noted in the margin: 'James = the brother of Jesus, him called Christ' (cf. the wording of Mt. 1:16: 'Jesus, him called Christ') and a later copyist took this note as belonging to the text and incorporated it. Other interpolations are known to have originated in precisely such a way.