Sentence:  After mentioning these facts, Shahristâni adds that "whatever befell them was prognosticated by Jaafar as-Sâdik, who said that temporal dominion was not for their family, but that the <WSD>Imâmate</WSD> was to be a toy in the hands of the Abbassides." 
Meaning of the word marked with <WSD> tags:  The office or jurisdiction of an imam.