It is named after the central panel, which shows
Saint Ildefonsus's vision of the Virgin Mary, in which she gave him a casula. On the side panels are
Isabella Clara Eugenia and
Albert VII, regents of the Spanish Netherlands, with their patron saints Albert [Note 1] and
Elisabeth of Hungary. Albert had founded the Ildefonso Brotherhood in the church of
Saint Jacques-sur-Coudenberg in
Brussels, to encourage loyalty to the Habsburg dynasty - the altarpiece was commissioned for the Brotherhood by his widow shortly after his death.
Notes
^There are many saints called
Albert. The figure in the painting is wearing the
habit of a member of the
Dominican Order. That seems to reduce the number of possibilities to one:
Saint Albert the Great. Albert VII was born on 13 November 1559. It was customary in the Roman Catholic church at that time to
christen children on the second or third day after birth. If Albert VII was christened on 15 November 1559, he will have been named after, and his patron saint will have been, that Saint Albert, whose
feast day it was.