The authors aim to explore and analyze the beginnings of the modern world religion of Islam using sources that anyone can verify, simply to understand how things actually were back then. The Quran plays a particularly important role in this, as it was from the circles of its producers and followers that Islam emerged as an independent religion around the year 800. However, our previous focus on the first three or four centuries of the Islamic calendar needs to be somewhat relaxed, as the intensive examination of the sources increasingly shows that many characteristics of Islam only took shape much later, and it is only since Saladin that we can speak of a Sunni Islam as we know it today. When investigating the contemporary sources – the Quran, coins, inscriptions, archaeological evidence, literature, and language history – it becomes increasingly clear that the "real" history unfolded differently than what the Islamic legends of later times portray. These legends are retrospective constructions of a "sacred history," which, like all such narratives, do not withstand scrutiny with the critical methods of historical science. In history, everything – or very much – has unfolded quite differently than previously assumed and as disseminated in "scientific" literature and on the internet.