The Austrian Freedom of religion has a long development behind itself, which can be traced back to ancient history. Only a more exact understanding of this development process allows a deeper understanding of religious freedom. Hence, this work shall show the essential developing steps of the religious freedom since the rise of the Christianity in the Roman Empire in detail. Besides, the representation goes beyond a pure enumeration of the legal basis and also treats their backgrounds and contexts. However, this work is also not satisfied with a purely legal-historical representation, also the current state of religious freedom is represented to merge together around the single development strands and to allow the reader a comprehensive picture of religious freedom thus. At the end of this work the reader should not only own a comprehensive understanding of religious freedom, but also he should can discuss on a professional level about past and future developments.