‘A Most Pious Prince’?

The Polish monarchy’s diplomacy in the 1520s and 1530s has long struck historians as peculiar—both pro- and anti-Reformation simultaneously. King Sigismund actively promoted Lutheran princes such as Duke Albrecht of Prussia or Wilhelm of Brandenburg-Ansbach in their activities in Livonia, Scandinavia, and the Holy Roman Empire, and married his oldest daughter to a leading Lutheran German prince. At the same time, a key facet of Polish diplomacy was the cultivation in speeches, treatises, and woodcuts of King Sigismund’s international reputation as a most pious prince. This chapter argues that, rather than diagnosing sixteenth-century diplomacy as pure realpolitik, we should pay attention to cultural factors in play, such as sacred bonds of kinship, the power of princely reputation, and ecclesiological beliefs. In these years, the Polish Crown conducted a pre-confessional diplomacy, in the conviction that Christendom was still one, perceiving relatively limited differences between Catholics and Lutherans.