When Martin Luther (1483–1546) published his 95 theses in Wittenberg, Coburg and the surrounding territory belonged to the electorate of Saxony as its southernmost region. The new doctrine arrived with the theologian Balthasar Düring (d. 1529). Düring came from Lower Franconia and studied at the University of Leipzig. In 1520, he began his ministry as a vicar to Saint Maurice, the main church of Coburg. In 1521/22, he was appointed to the vacant preaching office. His evangelical sermons enjoyed great popularity.
Düring’s significant participation led to the creation of a new order of service, which the elector approved in 1524 at the request of the city council and of the local electoral officials. The protest of the bishop of Würzburg in charge remained ineffective. In 1525, the dissolution of the monasteries began and the Reformation spread to the surrounding parishes.
The Reformation reached a first conclusion in the territory with the visitation carried out from mid-November 1528 to the end of February 1529 by order of Elector John the Steadfast (1468–1532, elector 1525–1532). In Coburg and Eisfeld, superintendencies with a supervisory function were created.
After the visitation, in June 1529, the neighbouring town of Rodach was the meeting place of the confessional alliance of the Protestant states of the Empire, formed in Speyer with the participation of electoral Saxony. The meeting is part of the history leading to the formation of the Schmalkaldic League in 1531.
Even though Elector John the Steadfast travelled to Augsburg in 1530 for the diet, Martin Luther had to stay behind at the fortress of Coburg because of the imperial ban. From here, he followed the events until his return to Wittenberg on 4 October 1530, maintaining a lively correspondence and receiving visits from important personalities. Several times, he preached in the Morizkirche (Saint Maurice). During his stay, Luther composed 16 important confessional and polemic writings.