On 31 October 1517, Martin Luther sent 95 theses to Albrecht of Brandenburg, Archbishop of Mainz and Magdeburg. They were attached to a letter. In 95 separate points, they spoke out against the business of selling letters of indulgence. Luther took the problem to the archbishop who shared in the proceeds.
The famous picture of Luther nailing the theses to the church door in Wittenberg is not certain. The Catholic church historian Erwin Iserloh first questioned it in 1961.