求翻译：第七世纪时，波斯人对于信奉伊斯兰教的阿拉伯人异军突起一事毫无防备。636年，波斯的萨珊王朝在此时于战乱中结束。由于波斯人没有一个在防御功能上可以与君士坦丁堡相比拟的首都，因而在651年被回教徒彻底征服。是什么意思？

The seventh century, Muslim Arabs, Persians for the sudden emergence of the issue unprepared. 636 years, the Persian Sassanid dynasty ended at this point in the war. As the Persians not a defense can be compared with the capital of Constantinople, which in 651 was the complete conquest of Muslims.

The first 7 century, when the Bosnian people believe in Islam The Arabs a rustic unsuspecting. In 636, the Sassanid Persia at this time to end the war. Because no one can be on the defensive functions with comparable to Constantinople in 651, the capital, and thus wiped out by Muslims.

When seventh century, the Persian regarding believes in Islamism the Arab sudden appearance of a new force incident not to guard against.636 years, Persia's Sa shan dynasty ended in this time in the chaos caused by war.Because Persian has not been possible to compare in the defense function with Con

The seventh century, Persian, Muslim Arabs sudden emergence of an unsuspecting. 636, this time to the end of the war in the Persian Sassanian Dynasty. Because Persians do not have a on the defensive function can be comparable to the capital of Constantinople, and 651 was completely conquered by Musl

The seventh century, Muslim Arabs, Persians for the sudden emergence of the issue unprepared. 636 years, the Persian Sassanid dynasty ended at this point in the war. As the Persians not a defense can be compared with the capital of Constantinople, which in 651 was the complete conquest of Muslims.