Lorenzo and Jacopo Salimbeni, John Denounces Herod, from The Life of John the Baptist
Oratory of St. John the Baptist, Urbino, Italy
This panel from the cycle assumes that Herod himself was present for John's "brood of vipers" sermon, in which he denounced Herod for marrying his brother's wife (Luke 3:7-20, compare Matthew 3:7-12). Mark 6:20 says that Herod took an interest in John's teachings "and he heard him willingly." In any case, it was the denunciation that led Herod to put John in prison.
The scroll in John's hand has the ECCE of Ecce agnus Dei, but the other word is either a garbling of AGNUS or some other word I cannot identify.
As usual in the works of the Salimbenis and many others, John wears an unbiblical toga-like garment over his camel-hair tunic.
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Detail of the crowd
Detail of the man in white
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Photographed at the site by Richard Stracke, shared under Attribution-NonCommercial-ShareAlike license.