The Muslim Empire
For the other great empires, religions were started because of the empire. But in this case, the empire was started because of the religion. (Islam)
The religion of Islam was started around 600 AD by a man named Mohammed, in Mecca, Saudi Arabia. It spread out of Mecca, East to the Indian culture, West across North Africa, and on into most of Spain.
The empire grew because of the spread of the religion to other people, and military conquest. The Muslims were fantastic fighters; they believed that if they died in battle, they would go directly to heaven, so they were less fearful. And, when they did capture people, they were treated very fairly, usually even better than the previous rulers. They would give them anything they needed; as long as they converted to Islam.
From around the years 700 AD to 900 AD is considered to be the Muslim "golden age", because of the of the contributions, great learning, and cultural diffusion that was happening. The Muslims were amazing learners, and they desired to know more, even in a time when most of the world was in the Dark Ages. They discovered things such as mathematics, astronomy, medicine, architecture, banking, and Islamic law. Many of the things that the Muslims worked on and learned are still things we use today.
In math, the Muslims spread the Gupta's math ideas, and created algebra and trigonometry. In astronomy, they learned from Greek ideas and studied the stars. they measured and mapped and created astronomical tables. In the field of medicine, Islam helped to create hospitals, and even came up with the idea that doctors should have to pass an exam before they were able to practice medicine. Also, important medical textbooks were created during the Muslim Empire.
The banking system used was somewhat modern; money was used, and credit was allowed for those that needed it. The Muslim Empire's architecture was influenced by the Byzantine and Indian styles that they encountered when the religion was spread. Things such as the onion shaped dome and the arches were used. Many buildings in Spain are still standing from the Muslim Empire that portray the classical Muslim style.
Just like the Byzantines, the Muslims would become preservers of the Roman And Greek ideas. They also improved them further, translating Roman writings and learning new things from the old ideas.