without his knowledge or prior approval, they were copied and printed across Germany and internationally. Different reformers arose more or less independently of Luther in 1518 (for example Andreas Karlstadt, Philip Melanchthon, Erhard Schnepf, Johannes Brenz and Martin Bucer) and in 1519 (for example Huldrych Zwingli, Nikolaus von Amsdorf, Ulrich von Hutten), and so on. After the Heidelberg Disputation (1518) where Luther described the Theology of the Cross as opposed to the Theology of Glory and the Leipzig Disputation (1519), the faith issues were brought to the attention of other German theologians throughout the Empire. Each year drew new theologians to embrace the Reformation and participate in the ongoing, European-wide discussion about faith. The pace of the Reformation proved unstoppable by 1520. The early Reformation in Germany mostly concerns the life of Martin Luther until he was excommunicated by Pope Leo X on 3 January 1521, in the bull Decet Romanum Pontificem. The exact moment Martin Luther realised the key doctrine of Justification by Faith is described in German as the Turmerlebnis. In Table Talk, Luther describes it as a sudden realization. Experts often speak of a gradual process of realization between 1514 and 1518. Reformation ideas and Protestant church services were first introduced in cities, being supported by local citizens and also some nobles. The Reformation did not receive overt state support until 1525, although it was only due to the protection of Elector Frederick the Wise (who had a strange dream the night prior to 31 October 1517) that Luther survived after being declared an outlaw, in hiding at Wartburg Castle and then returning to Wittenberg. It was more of a movement among the German people between 1517 and 1525, and then also a political one beginning in 1525. Reformer Adolf Clarenbach was burned at the stake near Cologne in 1529. The first state to formally adopt a Protestant confession was the Duchy of Prussia (1525). Albert, Duke of Prussia formally declared the "Evangelical" faith to be the state religion. Catholics labeled self-identified Evangelicals "Lutherans" to discredit them after the practice of naming a heresy after its founder. However, the Lutheran Church traditionally sees itself as the "main trunk of the historical Christian Tree" founded by Christ and the Apostles, holding that during the Reformation, the Church of Rome fell away. Ducal Prussia was followed by many imperial free cities and other minor imperial entities. The next sizable