The Islamic Caliphate that ruled in Baghdad, Iraq right now. This Caliphate rising power after defeating the Umayyad dynasty from all except Andalusia. The Abbasids established by the descendants of the Prophet Muhammad's uncle was the youngest, Abbas. Developed over two centuries, but slowly faded after the rise of the Turkish soldiers that they form (Mamluk). Fall of the total in the year 1258 due to attacks by the Mongols led by Hulagu Khan, who destroyed Baghdad and did not leave one bit of knowledge gathered in the library of Baghdad.