During his stay at Prague from 1574 to 1580, Edmund Campion completed three neo-Latin dramatic works, which were performed at the Clementina, the Jesuit academy where he served as a professor of rhetoric. Campion’s Ambrosia, a play about the life of St. Ambrose first performed at the Jesuit academy in 1578, explores the issue of ecclesiastical supremacy in a way that serves as a lens through which one can better understand how Catholic exiles generally understood the relationship between temporal and spiritual magistrates.1 It also provides some perspective on Campion’s cosmopolitan perspective in the Decem rationes, which I have explored at the beginning of Chapter 1. Before considering how Campion’s drama approaches the issue of supremacy, however, it is worth describing the contours of the events depicted within the play. The events begin in 386 CE, with tensions breaking out between Empress Justina, who ruled the Italian and African sphere of the Roman empire, and Bishop Ambrose of Milan. Empress Justina, whose court was based in Milan, was a champion of Arianism, which Bishop Ambrose and the church considered a heresy.2