Creation of Islam

IMHO, there is no such thing. Just cult leaders, petty ones and larger-than-life ones.

The really good ones are able to do just what you describe: they take bits and pieces and build a brand new model. Like a car manufacturer. They use succesful things from earlier designs, add a few new twists, and come out with a shiny new religion. The petty ones just mimic the great ones in a watered-down sort of way, and are quickly forgotten.

The really great ones are very rare, because it requires a very unique combination of talents. They have to be brilliant, true geniuses, in order to create a very appealing religious system which can mesmerize people, and they have to be extremely charismatic to get it off the ground. Genius and charisma tend to be a rare combination, all the more so when both qualities are taken to such extreme heights. Figures like this were probably like a cross between Einstein and Kennedy (or, perhaps to be more current, Obama and Stephen Hawking).

You get a combination like that and they're going to do something incredible ... really transform the world, shake it to its roots ... even though I don't consider them to have been talking directly to God, I can definately understand how such a person could give that impression. It would very much seem that way if you were to meet someone like that in person. Some of them probably posed as gods, themselves.