This document provides a summary of the history of the Muslim Ummah (community) over different time periods from the era of the Prophet Muhammad to modern times. It discusses the periods of Khilafah (Caliphate), kingship under various dynasties, the decline of the Ottoman Caliphate after World War 1 and the end of the Caliphate in 1924. It highlights the golden age of scientific achievements in the Islamic world from the 8th to 13th centuries and what led to its decline. Currently, Muslim countries contribute little to science and publish few academic papers despite their large populations.