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Wow. Bullseye. He just dunked on your head, and that's your only response? You fail.
The Islamic calander begins with the Hijra, Muhammad's immigration to Yathrib, NOT when Gabriel recited the Koran to him. It just goes to show the importance of his immigration and political takeover of the city, which was re-named Medina. Islam is a political ideology that masquerades as a religion, and Muhammad made up the Koran as he went along to suit his needs, which is why there are so many oddly specific laws such as the right to marry your own daughter in law.
"The Byzantine Empire, and the Muslims, according to the book Civilization Past & Present, (multiple copyrights), preserved Greek and Roman civilization." -- actually that's a myth, and the book addresses that. It also goes on to say that Islam opposes "bida" or innovation, because it creates confusion.
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