Re: If they had a time machine...
>especially given Islam was one of the most well documented historical religious movements.
I have to disagree as many sources suggest that Mohammed and the first couple Khalifs and even Mecca were all fictitious as accounts of these historic figures and places are very uncommon outside of Islamic oral traditions. Traditions, I might add, that many Islamic scholars disagree over.
An example is that the first non-Islamic historic reference to Mohammed is found on a Jerusalem coin, minted in ~ 720CE, almost 90 years after Mohammed died in 632CE.
Consider that Jerusalem was held by the Byzantine Empire (ex Romans + Greeks) before capture by Arabs (or Islamic forces led by the first Khalifa as the oral tradition tells it) in 637CE, there are very little accounts from Greek/Roman/Byzantine bloggers of organised Islamic traditions at the time (i.e. there are no recorded accounts visible Islamic traditions like communal Friday prayers etc).
Okay, so they didn't blog back then but historical bureaucratic documents were produced by Jerusalem's governors, tax collectors, Greek merchants and scribes... none of which attribute Islamic behaviours to the conquering Arabs.
Pint, as I am a Real Ale enjoying apostate.