One issue is in Australia, they protested for the immigration of Muslim people. It was a self-defense mechanism from outside nationalities and a counter to things that they would encounter in the future. They wanted to have more entitlement because they are the real citizens of their own soil. Data came from abc.net.au/news.
Success in trade always deals with advertisement. In this case, the spread of Islam help distribute it's teachings and beliefs making more people contribute to trade.
Answer:
the answer is airplanes/planes :)