The Peace of Augsburg in 1555 was significant as it marked an important legal resolution to the religious conflicts in the Holy Roman Empire. The treaty allowed for the coexistence of Catholicism and Lutheranism, establishing the principle of "cuius regio, eius religio," meaning that the ruler of a territory would determine its religion. This agreement helped to temporarily quell religious wars by providing a degree of autonomy to different regions, laying the groundwork for the eventual Treaties of Westphalia in 1648, which further shaped the political landscape of Europe.