(This is a modified version of a question asked on the Nyingma page.) In Gelugpa circles, Tsongkhapa is said to be the embodiment of three deities: Avalokitshvara, Manjushri, and Vajrapani. I am wondering where this grouping came from, if it was not originally Gelugpa. I am aware of the tradition of the three dharma emperors being manifestations of these three deities, respectively, but lately I read that Sakya Monastery is said to have had one manifestation of Avalokiteshvara, seven of Manjushri, and one of Vajrapani. (I do not know who these refer to.) Perhaps this is the source, or one of them. Is there a Sakya tradition of grouping these three deities together?