Zaydids

In the 9th–14th centuries, the northern Iranian regions of Tabaristan, Daylam and Gilan, sandwiched between the Caspian Sea and the Alborz range, came under the rule of a number of Alid dynasties, espousing the Zaydi branch of Shi'ism. The first and most powerful Zaydi emirate was established in Tabaristan in 864 and lasted until 928. It was interrupted by Samanid occupation in 900, but restored in 914 by another Alid branch. The second period of the Alid emirate was plagued by internal dissensions and power struggles between the two branches, and ended in the second conquest of the region by the Samanids in 928. Subsequently, some of the soldiers and generals of the Alavids joined the Samanids, among them the founder of the Ziyarid dynasty, Mardavij, and Ali, Hassan and Ahmad, the sons of Buya and founders of the Buyid dynasty.