Zayd ibn Ali
The Zaydis, Twelvers, and Ismailis all recognize the same first four Imams; however, the Zaidis consider Zayd ibn Ali as the fifth. After the time of Zayd ibn Ali, the Zaidis believed that any descendant of Hasan ibn Ali or Hussein ibn Ali could be imam after fulfilling certain conditions. Other well-known Zaidi Imams in history were Yahya ibn Zayd, Muhammad al-Nafs al-Zakiyya and Ibrahim ibn Abdullah.