The Fatimid Dynasty was a significant Islamic caliphate that emerged in the 10th century, founded by Ubayd Allah al-Mahdi Billah in 909 CE. It was named after Fatimah, the daughter of the Prophet Muhammad, and claimed descent from her. The dynasty initially established its capital in Mahdia, Tunisia, and later moved to Cairo, Egypt, which became a center of culture and learning. The Fatimids were known for their promotion of Ismaili Shia Islam and their architectural achievements, including the famous Al-Azhar Mosque. The dynasty reached its peak in the 11th century, controlling parts of North Africa, the Levant, and the Arabian Peninsula before declining in the 12th century.