Did you know Al-Battani?

We Muslims ruled the world for around 12 centuries. the reason for such a power is because the Muslims were stick to the religion. Muslims were very much Advance in Education, Economy, Military, politics and etc.
Europeans call the period of 8th to 12th century the Dark Age. Dark for whom? Dark for the Europeans, not for the world.
Arabs and the Muslims were very much advance from 8th -12th century. Europeans were backwards in that age. It was the Golden Age for the Muslims and the world !
With the limited instruments and technology what the Muslims had from 8th - 12th century the the amount of Scientific discoveries made, it's unbelievable !

http://en.wikipedia.org/wiki/Muslim_scientists

Ultimately the Crusaders came away with no permanent conquests, they destroyed universities, libraries, and education centre of the Muslims. And they returned with something even more valuable. That's the knowledge from the Muslims.
The Europeans picked up the discoveries of the Muslims and claimed that they were the first to discover.
For an example, Ibn Nafees first discovered the blood circulation, but in western books it's William Havi. Ibn Nafees discovered the blood circulation 400 years back. Who knows about Ibn Nafees? It's the western Media.

In the early stages of Islam almost all the massive battles were won by the Muslims (Muslims fought on self defence or to make Justice prevalent and to eradicate the evils of the society); Despite the Muslims were least equipped, low numbered and enemies were very well equipped, outnumbered. It's not the Military power which gave the Muslims huge victories. It's the strong faith, steadfastness, obedience to Allah and his Messenger (sal) of the Muslims !