In May 1608, several Protestant rulers in the Holy Roman Empire convened an emergency summit in the Swabian town of Auhausen. Weeks earlier, they had walked out of the Imperial Diet, the Empire’s main legislative assembly, to protest what they deemed Catholic attempts to undermine the Empire’s constitution. Speaking in one voice, those gathered in Auhausen condemned their opponents’ “hostile and violent actions” as a threat to the Empire and its members, known as Imperial Estates. If left unchecked, rogue actors would “create one disturbance after another in the beloved Fatherland, thereby wreaking havoc with the entire ancient and praiseworthy imperial constitution. The result will be nothing less than the destruction of all good order, law, and prosperity.” Only by uniting “in a loyal understanding and association” could peace-loving authorities prevent this catastrophe. Accordingly, the Estates assembled in Auhausen formed an alliance, set to last for ten years, which became known as the Protestant Union.