I have spent a lot of time looking into this subject and speaking with some historians of islam at Oxford uni about it and they have all confirmed to me what I wrote about the first official codification of Koran being written by islamic scholars in baghdad in 741AD ,,, they do admit that the caliphs were collecting writings and testaments ,, but also state that the actual existance of mohammed is unlikley and that he is a mix of peoples stories and experiences ,, Archaological studies in the 1950s and again by the saudis when building in the 1980s confirmed the lack of any developments at Mecca pre 8th century apart from the pagan shrine ... This was a dissapointment to the saudis and they dont like to admit it .....A well was dug at mecca in mid 8th century and modern Mecca has a huge desalination plant with pipelines from the Red sea to supply the city ,, Ironicly it was Built by Bechtel an American firm ......