Zaydid was the name of an Alid dynasty that ruled Tabaristan. This dynasty is called Alid because are descents from Ali, son-on-law of Muhammad.
The Zaydid dynasty of Tabaristan are descents from Ali ben Abi Talib . His son, Hasan ben Ali, has a son named Zayd ben Hasan that gave name to the dynasty. Haan ben Zayd was the soon of Zayd that give origin to the Zaydids in Tabaristan.
