Chapter 6 examines the lead up to the Thirty Years‘ War through the lens of two opposing alliances: The Protestant Union and the Catholic Liga. Founded in 1608 and 1609, respectively, both leagues positioned themselves as protectors of the imperial constitution, even as their members could not agree with each other over how best to defend the Empire’s vitality. Conflicting visions dominated the Union and Liga, as small and large Estates clashed over each league’s scope of action. Smaller Estates saw each alliance as a way to conserve existing rights and conditions, while some princely members sought to use the alliances to pursue their own innovative plans for the Empire. These divergences echoed the debate over the League of Landsberg’s failed expansion from forty years earlier. Ultimately, each alliance’s smaller Estates successfully imposed their vision on the larger Estates during a controversy over the Union’s invasion of Alsace in 1610. The patterns established in 1610 ultimately determined how each alliance reacted to the later crisis in Bohemia that began in 1618.