Throughout its existence, the inhabitants of the Holy Roman Empire frequently evoked concepts of peace in legal, governmental, and moral affairs. In particular, the term Landfrieden can be found in sources from the thirteenth to the eighteenth centuries. Historians and legal scholars have long debated its meaning, typically defining it either as a form of legislation or else as a type of regional peacekeeping union. This chapter synthesizes the array of evidence regarding Landfrieden and makes the argument that it was central to discourses about public peace and authority in the pre-modern German lands, which could find expression within both regional and pan-imperial organizations, laws, and institutions. The chapter surveys concepts and applications of Landfrieden from the high medieval period to the Holy Roman Empire’s dissolution in 1806, demonstrating how it could legitimize leagues, alliances, and other associations while also underpinning the evolving imperial constitution.