There was a book out about twenty years ago (western author) naming individuals he felt most influential in human history. He put Mohammed at the top.

Regarding Muslims prior to Mohammed. Mr. Burke's well written chronology is correct, but I'd add there is a component to Islam itself which 'adjusts' perceived inaccuracies in the existing scriptures. Therefore Abraham (Ibraham) becomes the first Muslim, God (Allah) didn't need to 'rest' on the seventh day, Jesus (Issa) while a holy man was not divine in nature, etc. In other words, the Torah, once amended, becomes an Islamic 'prequel'.

This is not that odd. Mormons have a practise of 'baptizing' (There's prob'ly a better Mormon term I'm not aware of) into the faith their ancestors and great figures in history. There was a newspaper story that there was a Mormon project to 'baptize' into the faith victims of the Holocaust.

Early Christians had the task of rectifying New Testament theology "None gets to the Father save through the Son" with Christian prehistory. I think that's how the theory of limbo got devised.