Winged altarpiece whith the Holy Kinship

The work provides a rare example of altarpieces with doors, entirely painted and without sculptures. The central board depicts the theme of the Holy Kinship. The doors of the altarpiece show the figures of Saints Catherine of Alexandria and Barbara on the feast day side, and Saints Christopher and Erasmus on the weekday side.

The Holy Kinship is an image with a legendary background, inspired by the Golden Legend, which was developed as a response to the so-called problem of “Jesus' brothers”, mentioned in some passages in the Gospels.
According to this tale, Anne, after being widowed of Jacob, married for the second time, to his brother Cleophas. Being widowed for the second time, she married a third time, to another of Joachim’s brothers, Salomas.
From each of the three weddings, Anne is said to have had a daughter named Mary. The first Mary (the Madonna) married Joseph and had a single son (not conceived carnally, but rather through the work of the Holy Spirit), Jesus. The second Mary (daughter of Cleophas) had four children with her husband Alpheus (James the Minor, Joseph the Just, Simon, and Jude Thaddeus). The third Mary (daughter of Salomas) had two children with her husband Zebedee (James the Greater and John the Evangelist).
According to this version, censored by the Council of Trent, five of the twelve apostles would be Jesus’ first cousins, or his brothers because - as Saint Jerome taught - in Hebrew the term for “brothers” may also include first cousins.
Two of the Mary’s mentioned by the Gospels would therefore be sisters of the Virgin and, like her, Anne’s daughters.