The Augsburg Interim was an imperial decree ordered on 15 May 1548 at the 1548 Diet of Augsburg by Charles V, Holy Roman Emperor, who had just defeated the forces of the Protestant Schmalkaldic League in the Schmalkaldic War of 1546/47. Although it ordered Protestants to readopt traditional Catholic beliefs and practices, including the seven Sacraments, it allowed for Protestant clergymen the right to marry and for the laity to receive communion in both kinds. It is considered the first significant step in the process leading to the political and religious legitimization of Protestantism as a valid alternative Christian creed to Roman Catholicism finally realized in the 1552 Peace of Passau and the 1555 Peace of Augsburg. The Interim became Imperial law on 30 June 1548. The Pope advised all bishops to abide by the concessions made to the Protestants in the Interim in August 1549.

The diets of Augsburg were the meetings of the Imperial Diet of the Holy Roman Empire held in the German city of Augsburg. Both an Imperial City and the residence of the Augsburg prince-bishops, the town had hosted the Estates in many such sessions since the 10th century. In 1282, the diet of Augsburg assigned the control of Austria to the House of Habsburg. In the 16th century, twelve of thirty-five imperial diets were held in Augsburg, a result of the close financial relationship between the Augsburg-based banking families such as the Fugger and the reigning Habsburg emperors, particularly Maximilian I and his grandson Charles V. Nevertheless, the meetings of 1518, 1530, 1547/48 and 1555, during the Reformation and the ensuing religious war between the Catholic emperor and the Protestant Schmalkaldic League, are especially noteworthy. With the Peace of Augsburg, the cuius regio, eius religio principle let each prince decide the religion of his subjects and inhabitants who chose not to conform could leave.