Excerpts from Books and Wikipedia
". . . the sack of Baghdad and the destruction of the Abbasid caliphate was one of the worst atrocities committed by the Mongols. The House of Wisdom, a vast library of scientific and philosophical texts built up over 500 years, was destroyed, and tens of thousands of books were flung into the Tigris, turning its waters black with ink. . . . The Mamluk rulers of Egypt, however, were not cowed, and it was at their hands that the Mongols suffered a significant defeat, at the battle of Ain Jalut in 1260, which ended their westward rampage across the world." [Furtado: 1001 Days] Generally considered the end of the Islamic Golden Age." [Wikipedia: Timeline of Middle Ages]