The article considers the causes of the Thirty Years War in the light of modern historiography. Why did not they manage to agree on the ruling elites of Germany on the eve of 1618? Why do German historians today avoid viewing the prewar decade as an inevitable prologue to a crisis? Why did the balance of power in the Holy Roman Empire turn out to be stable on the eve of 1618? In the center of attention: the policy of the pre-war emperors from the house of the Hapsburgs, the leaders of religious-political groups, the public opinion of Germany. The article provides a detailed analysis of the structures of hostile groups — the Catholic League and the Union. Considerable attention will be paid to the diplomacy of the leading princely houses of Germany, primarily the electors of Saxony, Brandenburg, and the dukes of Bavaria on the eve of the Thirty Years' War.