The article examines the deepening of relations between Saxony and Prussia in 1778. It investigates the reasons behind the Dresden court's reorientation of foreign policy, marked by its decision to abandon an alliance with the Habsburgs in favor of a pact with the Prussian king on the eve of the Bavarian Succession War. The study aims to uncover the motivations of Saxon policymakers, who, amid deteriorating relations with Austria, sought protection for their state's sovereignty and territorial integrity in Berlin—a power that had long pursued policies detrimental to Saxony's interests. Furthermore, the article features an edition of a previously unpublished Saxon-Prussian convention from March 1778, preserved in the Sächsisches Hauptstaatsarchiv in Dresden.