yeah even i had a picture in my head that islam started way in the desert by some isolated people who also happened to acknowledge jesus, but from the points shakka made and some of the links ive been reading the links between islam and christianity are quite deep, its quite accurate to say that islam came from christianity the same way christianity came from judiasm
in other words islam isnt the brother of christianity, its the son
yea you absolutely right
I would just add that Christianity is not the only influence on Islam.