The Caliph is the head of state in a Caliphate, and the title for the ruler of the Islamic Ummah, an Islamic community ruled by the Shari’ah. It is a transcribed version of the Arabic word Khalifah (help·info), which means “successor” or “representative”. Following Muhammad’s death in 632, the early leaders of the Muslim nation were called “Khalifat Rasul Allah”, the political successors to the messenger of God (referring to Muhammad). Some academics prefer to transliterate the term as Khalifah. A Calipha is the wife or widow of a caliph or (rarely) female caliph, there was one known instance in history that a calipha was regent and ruler of a Caliphate, Sitt al-Mulk was regent of the Fatimid Caliphate from 1221 to 1223.