Leonhard Schiemer (c. 1500 – 14 January 1528) was an early pacifist Anabaptist writer and martyr whose work survives in the Ausbund.
Schiemer was born around 1500 in Vöcklabruck, where he grew up in a religious environment and trained to be a tailor. He originally wanted to become a Roman Catholic priest but as an adolescent joined the Franciscan monastery in Judenburg. Six years later he left he monastery and arrived at Nürnberg, where he — disappointed with monastic life — returned to tailoring.
Biographers disagree whether Schiemer first made contact with Anabaptists in Nürnberg. Schiemer may have made arrangements to travel to Nikolsburg in Moravia, where Balthasar Hubmaier was an important Anabaptist leader. Here he witnessed the May 1527 disputation between the Stäbler (shepherd's staff) und Schwertler (sword) Anabaptist groups. While the Stäbler under the leadership of Hans Hut held a position of absolute nonviolence, Hubmeier and the Schwertler professed that Christians were permitted defend themselves and others with the sword. It is unknown which of these positions Schiemer adopted. Some biographers think he probably adopted Hubmeier’s view, because later in Vienna he was reluctant to accept Hans Hut.
Only a few weeks after the Nikolsburg disputation Leonhard Schiemer went to Vienna. There he again met — as already mentioned — Hans Hut and the Anabaptist congregation at Kärntnerstraße. Within two days, Schiemer was won over to the Anabaptist view and at the same time convinced of the pacifist beliefs of the Stäbler. He was baptized and became a member of the Vienna congregation.