From the era of Muhammad (ca. 622 CE) until the founding of independent sub-states in many parts of the Yemen Islamic Caliphate, Sanaa persisted as the governing seat. The Caliph's deputy ran the affairs of one of Yemen's three Makhalifs: Mikhlaf Sanaʽa, Mikhlaf al-Janad, and Mikhlaf Hadhramaut. The city of Sanaa regularly regained an important status, and all Yemenite States competed to control it.