The god of islam "Allah", was in fact around a long time before muhhammad started the religion of islam. In fact, the arabs used to worship 3 gods and allah was in fact the moon god worshiped by arab tribes people (this is were the islamic symbol of the cressent moon & star comes from).
History has it, but will be debated strongly by muslims, as it discredits their relgion, that when muhhammad needed to choose a god, he could not, so he wrote the three god's names down on individual paper, placed the three pieces into a hat and drew only one and that one was the god allah.
There is a lot of truth to the real history of the creation of islam and most of it over time has been deceptive & false, but covered up by lies and other methods of deception by muhhamad himself (doomsday, burn in hell for questioning gods word etc written throughout the qu'ran). However, like the christian faith, islam grew the same way, had it's own crusades (muslim invaders, sword of islam) and established it's place in the world as an accepted faith due to its number of followers.
The visions and messages that both Jesus & Muhhammad had experienced, can be experienced by anyone through deep meditation. Even Buddha himself experienced this and preached the same things as Jesus & Muhhammad did long before them. Unlike Jesus & Muhhammad, he didn't have to go around claiming to be a messanger of a god, but just a human like everyone else (of course there where those who will always distort this immage of buddha as superhuman).
As time goes on and we become more advanced and collect & research more information, much truth will come out that will discredit, expose lies & delibrate deceptions and flaws in every religion, because at the end of the day, religion was created by humans as a means of controlling human behaviour.