Excerpts from Books and Wikipedia
"The Arabs then excelled all the peoples of the world in science and the arts, in industry and invention, in philosophy, government and moral character. And truly, the rise of this brutish and despicable element, in such a short interval, to the supreme heights of human perfection, is the greatest demonstration of the rightfulness of the Lord Muhammad's Prophethood." [Abdu'l-Baha: The Secret of Divine Civilization, p. 88]
"Islam was nothing less than the return to the pristine monotheism of Abraham—abandoned or misunderstood by Jews and Christians alike, the revelations asserted, and unknown altogether to the benighted pagans of the desert. All this came forth not in Muhammad’s own words but through his transmission of the direct language of God, his “Recitation”—the word Quran means “recitation”—of what God was revealing and dictating to him." [Menocal: Ornament of the World, p. 18-9] Muhammad's revelation effected a transformation (Renaissance) in 12th century Europe. Also, the beginning of the Golden Age of China (the Tang Dynasty) was concurrent with the life of Muhammad.