Hasan ibn Zayd, wanda aka fi sani da Great Dai, (an haife shi a farkon ƙarni na 8, ya mutu 6 Janairu 884) shi ne sarki na Tabaristan na Alids . Ya yi tawaye a Tabaristan (a cikin 864) kuma ya yi yaƙi da Daular Abbasiyya Taheriya da daular Saffarids. Ya ƙirƙiro daular Alavids. ALIDS : Ecyclopedia Iranica