Tabaristan now came under Tahirid rule for over two decades. Quhyar, who had been promised by the victors possession of the kingdom of Vindadhhurmuzd, was killed by his brother's Dailamite slave guard, and it has been generally assumed that the Qarinvand dynasty came to an end at this time. This assumption is probably wrong. In events of the year 250/864 an Ispahbad of Lafur, Baduspan b. Gurdzad, is mentioned. He and his descendants through three generations are occasionally referred to until 318/930 as rulers of Lafur, Vinda-Umidkuh and Vindadhhurmuzkuh.
One of them is designated in a contemporary source as a Qarinid ("Ibn Qarin"). After 318/930 the dynasty apparently declined to insignificance and is not mentioned for over a century. But towards the end of the 5th/nth century Ibn Isfandiyar again mentions amirs of Lafur and expressly calls them Qarinvand. It is thus evident that Baduspan b. Gurdzad also must be a Qarinid, though his exact relationship to Mazyar is unknown.
The Bavandid Qarin b. Shahriyar, who also had aided the Tahirid conquest, in reward for his services was restored to the rule of the Sharvin mountains. In 227/842 he accepted Islam. The Islamization of the native population of Tabaristan was proceeding rapidly now. The majority adopted Sunni Islam loyal to the 'Abbasid regime, especially of the Hanafi and Shafi'I schools. But oppositional Shfism soon also spread.
Imamism found adherents especially in Amul and east of Tabaristan in Astarabad and Gurgan. In Ruyan and Kalar Zaidi ShTism was propagated by followers of the 'Alid al-Qasim b. Ibrahim al-Rassi (d. 246/860). One of the chief transmitters of the teaching of al-Qasim was Ja'far b. Muhammad al-Nairusl, a native of Nairus in Ruyan. From Ruyan with its close connections with the Dailamites - Ruyan had indeed formerly belonged to Dailaman - Zaidism began to spread westward to the Dailamites and Gilites living outside the territory of Islam.
Economic Enterprise of Zoroastrians
