San Ambrosio prohíbe la entrada a Teodosio en la catedral de Milán

Van Dyck was barely 20 when he painted this, working as the star assistant in Rubens's busy Antwerp studio. The composition is not really his own invention. It closely follows a larger picture Rubens had made a few years earlier, now in Vienna. The subject reaches back to the year 390, when Bishop Ambrose of Milan blocked the Roman emperor Theodosius at the church door, refusing him entry until he did penance for ordering a massacre of thousands in Thessalonica. Van Dyck reworked his master's design rather than copying it flatly. He firmed up the architecture and, at the bottom left, added a dog, a pointed touch, since Ambrose had told one of the emperor's men that he had no more shame than a hound. The young painter would soon leave for Italy and become the most sought-after portraitist of his day.