Bartolomeo Vivarini, St. Mark Enthroned

Tempera on Panel
Church of Santa Maria Gloriosa dei Frari ("the Frari"), Venice

St. Mark is identified by the label in the church, although the painting does not provide any attributes or inscriptions regarding that saint.

The label is clearly erroneous in its identification of the two saints on the right as Peter and Nicholas. Neither of them has Peter's traditional attribute, his keys. The one with the mitre and crozier is certainly the bishop St. Augustine, who is traditionally pictured in a cope whose hem bears embroidered images. Nothing in the painting identifies the other saint on the right as Nicholas, who is almost always portrayed with three gold balls or three boys in a tub. As a wild guess, he could be St. Hermagoras, whom Mark had St. Peter ordain as the first bishop of Aquileia, the see that eventually became the patriarchate of Venice.

On the left, the saint in the dark clothing is John the Baptist. His left hand holds a cross with a banderole reading ecce agnus dei, "behold the lamb of God" (John 1:29), and his right hand points as if to Jesus Christ. The saint in red is Jerome. He was often pictured with a maquette of a church in Dalmatia and Istria but nowhere else, as far as I know, except for this church in Venice, which also has a statue of him with the maquette.

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Photographed at the site by Richard Stracke, shared under Attribution-NonCommercial-ShareAlike license.