The paper deals with the question of religious tolerance in Europe's past and present. Tolerance within Christianity (and within the other so called "Abrahamitic" or "Biblical" Religions) is one of the main points. However, the reader is also invited to take a brief look at Europe's pre-christian past. To some extent, the religious situation of the Roman Empire in particular rather seems to resemble our own experiences with pluralistic societies in today's Europe than medieval and early modern circumstances would do. Even the ancient problems with "religious freedom" can be linked with modern counterparts. So this paper will avoid long retrospectives at the well known facts of Europe's Christian past such as inquisition and European religious wars in order to deal with some more hidden perspectives of European religious history, which were often obscured by the main historiographical narrative.