Why is Joseph as an old geezer in Nativity Scenes?

"Adoration of the Child," Master of the Divisio Apostolorum (c. 1470/80). Schloss Eggenberg, Alte Galerie, Graz, Austria.

Detail from "Adoration of the Child"

Ever wonder why Joseph is almost always portrayed as an old man in Nativity scenes? The reason goes back to an early apocryphal book--maybe as early as the 2nd Century AD--known as the Proto-Gospel of James. In the story Joseph is an elderly widower who marries the youthful Mary in order to take her under his care, as a father figure not as an actual husband. In the story, James the brother of Jesus is the son of Joseph by his previous marriage. The story marks an early departure from the New Testament view of Mary and Joseph as simply husband and wife and Jesus’s brothers and sisters as Mary and Joseph’s natural children. In contrast, The Proto-Gospel was interested in preserving the idea of the perpetual virginity of Mary, going as far as claiming that Mary was found to still be physically a virgin after Jesus was born (chapter 20). This then is the story that stands behind the way of depicting Joseph in Eastern Orthodox Iconography. 

From there the convention of an elderly Joseph was taken over by the artists of the Roman Catholic West and it has continued down even to present day Christmas cards and shopping-mall crèches. Curiously, though, the story as presented in the Proto-Gospel of James is not the accepted view of the relationship between Mary and Joseph and James in the Roman Catholic Church. The Catholic view is that James was a cousin of Jesus not his brother or half-brother. We see this for example in the Roman Catholic Liturgy of Hours, in its Office of Readings for May 3: as his brother or half-brother. 

James, a cousin of the Lord and the son of Alphaeus, ruled over the Church at Jerusalem, wrote and epistle and converted many of the Jewish people to the faith. He led an austere life and suffered martyrdom in the year 62.

The reason for the difference is that Jerome, the great fourth-century theologian and Bible translator, did not like the idea of Mary marrying a man, who had been sexually active, even if only in a previous marriage. “He who was thought worthy to be called father of the Lord, " Wrote Jerome in Against Helvidius 21, "remained a virgin.”

St. Jerome

In order to make this work the Western Catholic Church blended two New Testament James, James the Brother of Jesus and James Son of Alpheaus, into one person—James son of Alpheaus.

The Roman Catholic view founders, for one thing, on the fact that both James of Alphaeus (one of the Apostles) and Mary the mother of Jesus "and his brothers" are both mentioned in the same setting in the first chapter of Acts.

They went up to the upper room, where they were staying, Peter and John and James and Andrew, Philip and Thomas, Bartholomew and Matthew, James the son of Alphaeus and Simon the Zealot and Judas the son of James…All these [Apostles] with one accord were devoting themselves to prayer, together with the women and Mary the mother of Jesus, and his brothers” (Acts 1:13–14, italics mine). 

Strictly speaking then there is no real reason why Joseph should be old in Roman Catholic Nativity scenes, since on Jerome's solution, it wouldn't have mattered how old Joseph was when he married Mary.  Yet the practice persists largely because of reliance on works like the Proto-Gospel as a basis for Iconographical convention.