Islamic tradition rests on a foundation of the (claimed) writings of Muhammad, that we know as the Koran (or, Quran). So in that view believers see him restoring the original monotheistic faith of all the prophets ( of the west Asian tradition).
Its important to know that Muhammad was born in Mecca (in Arabia) somewhere around 570 CE. His parents died when he was young, and he was given into the care of his uncle Abu Talib. As an adult he mostly worked as a trader. For whatever reason he seems to have felt the need to be alone at times and would got to a mountain cave for meditation and prayer, and it was at this place that he tells of being visited by the angle Gabriel and given a revelation, specifically for him, from God. It is said that he was aged 40 at that time, Hence the earliest he could have started writing down these prophetic messages is around 610 CE.
But ...
We now come to a recent discovery. Filed away in a library in Birmingham UK was an old manuscript - contained part of the Koran. Like most ancient manuscripts these days, it was subjected to a battery of tests in an attempt to establish its age.
So now jump to the news story to see how old the experts think it may be and what the implications are for the dating: