The majority of Indonesia and Malaysia are muslims. Looking at it geographically and historically, how did Islam heavily influence these asian countries?

by FyDollarBill

Here is a picture showing muslim density. Surely the asian countries along the way to Indonesia and Malaysia should have a fairly dense population of muslims, correct? Or was it that Indonesia and Malaysia didn't have a structured culture and religion so they were easily converted to islam when muslim missionaries came over.

PangeranDipanagara

I discuss this extensively here.

CptBuck

Not to discourage other answers, but just to clarify and emphasize their response above, /u/PangeranDipanagara's answer knocks this out of the park.