The Abbasids ruled from 751-983 AD and established their capital in Baghdad. During their Golden Age from 775-861 AD, Baghdad became a global center for science, philosophy, medicine and education under rulers like Al-Mansour and Harun Al-Rashid. The House of Wisdom gathered knowledge from many cultures and advanced fields like algebra, geometry, astronomy, and the introduction of paper and the number zero. However, as the empire grew too large to govern effectively and rulers became distant from the people, rebellions emerged and the Abbasid Caliph became merely a religious figurehead by 930 AD, leading to their eventual decline.