So while the Islamic empire didn't require its subjects to convert to Islam, their stunning successes certainly convinced a lot of people that this monotheism thing was legit. Once again, John Green proving super hip to the slang of today's youngins. Also you paid lower taxes if you converted and just as taxes on cigarettes lead to people not wanting to smoke, taxes on worshipping your idols lead to people not wanting to worship them anymore. So in a period of time that was, historically speaking, both remarkably recent and remarkably short, a small group of people from an area of the world with no natural resources managed to create one of the great empires of the world and also one of its great religions. And that very fact may be why people of Western European descent remain largely ignorant about this period. Not only were the Muslims great conquerors, they spawned an explosion of trade and learning that lasted hundreds of years. They saved many of the classic texts that formed the basis of the so-called Western canon while Europe was ignoring them and they paved the way for the Renaissance.