The Peace of Augsburg was a treaty signed in 1555 that aimed to resolve religious conflicts in the Holy Roman Empire. It allowed rulers to choose either Lutheranism or Catholicism as the official faith of their territories, establishing the principle of "cuius regio, eius religio," meaning "whose realm, his religion." This agreement marked a significant step towards religious tolerance in Europe. The treaty was a response to the growing tensions between Protestants and Catholics during the Reformation. While it provided temporary peace, it did not fully resolve the underlying issues, leading to further conflicts, including the Thirty Years' War later in the 17th century.