I agree with most of the things Jake said. Islam at a time when people had so many problems, introduced a system which gave solutions to those problems. And that was the attraction of Islam. As Jake said, Christians and Jews (or any None Muslims) paid tax called “Jiziah” and as a return they were given safety (defence) by the Muslim rulers against other invading Christians and others. There have been incidents where when Muslims left the area they refunded their tax (Jiziah) paid in advance, then from Arab traders used to go towards Indonesia and used to sell all the dodgy stuff but after becoming Muslims they started telling buyers about the possible faults in their goods. So these minor things attracted the attention of the others.
Naomi – You may say that Muslims have differences but only well known are Shia and Sunni. But Quran clearly forbids these sorts of things.
Quran 3:103. And hold fast, all together, by the rope which Allah (stretches out for you), and be not divided among yourselves; and remember with gratitude Allah.s favour on you; for ye were enemies and He joined your hearts in love, so that by His Grace, ye became brethren; and ye were on the brink of the pit of Fire, and He saved you from it. Thus doth Allah make His Signs clear to you: That ye may be guided.
Allah’s rope here means Quran which is same. Muhammad (pbuh) and his companions were neither Sunni nor Shia. It all started later.
Muslims, when they acted upon Quran and Sunnah (life of Muhammad pbuh) saw their peak and produced pioneers of many fields out of people who werer never known for their knowledge. when they started straying away from that the decline started.