In Matthew 13:55–56 an awed crowd reacts to Jesus’ teaching in the synagogue of his hometown: “Is not this the carpenter’s son?” they say. “Is not his mother called Mary? And are not his brothers James and Joseph and Simon and Judas? And are not all his sisters with us? Where did this man get this wisdom and these deeds of power?”

That Jesus had siblings—attested by this and several other passages in the New Testament—comes as a surprise to many people, particularly now with the renewed interest in James, the leader of the Jerusalem church after Jesus’ death.

What was James’s relation to Jesus? Was he really his brother? What does “brother” mean, anyway, when talking about a man who is called the Son of God? These are complicated questions—and there has long been disagreement between different Christian (and non-Christian) traditions about how to answer them. There are four main opinions: The simplest one is that James was Jesus’ full brother—that James and Jesus were the sons of Mary and Joseph.

While it has the advantage of simplicity, this explanation does not mesh with most Christians’ belief that God, not Joseph, was Jesus’ father. There’s also another problem: In the seventh century, the church affirmed as one of its central dogmas that Mary remained a virgin even after she bore Jesus—which means that Jesus could not have had a brother related to him by blood. The traditional Roman Catholic interpretation has thus been that James was not Jesus’ brother but, instead, a first cousin—he is usually identified as one of the sons of Joseph’s brother (or brother-in-law) Clopas and his wife, who happened also to be named Mary. (That there are so many Marys and Jameses in the New Testament has caused much confusion for biblical scholars as well as readers!)

The Eastern Orthodox tradition, which also affirms that Mary was a perpetual virgin, has a somewhat different interpretation of who James was: James, in this view, is not a cousin but a stepbrother of Jesus—one of the sons of Joseph by a previous marriage, before he wed Mary.

Protestants, on the other hand, while accepting the divine fatherhood of Jesus have not been bound to uphold the doctrine of Mary’s perpetual virginity. Some Protestants have thus upheld the view that, after Mary bore Jesus, she went on to bear other children by her husband Joseph, and that James was one of them. So James, according to this view, would be Jesus’ younger half-brother.a

The 15th-century painting (above) from the Abbey of Neustift, Austria, shows the extended holy family as it is understood in a late Catholic tradition, recorded in Jacobus de Voragine’s Golden Legend (1260). According to this tradition, Mary’s mother Anne had three successive husbands. With each, she had a daughter. In this painting, Anne is seated at center, with her three husbands directly behind her: In Anne’s lap is the most famous of her three daughters, the Virgin Mary (in miniature), who is seated beside her own child, the infant Jesus. Mary’s husband Joseph stands second from the left, reaching toward Mary. The woman seated on the right is Mary of Clopas (also identified as a daughter of Anne in the Golden Legend), and on her knee are, from left to right, James the Lesser (labeled in Latin, Jacobus Minor), Joseph, Simon and Judas. The New Testament brothers are thus presented here as first cousins. Their father Clopas stands behind them, at far right. On the left, the apostle John (here identified with the evangelist) and the apostle James the Greater sit on the lap of their mother, traditionally called Salome and identified in the Golden Legend as yet another daughter of Anne. Behind them, at far left, is Salome’s husband, Alphaeus.