GUHYASAMĀJA. The term Guhyasamāja ("Secret Assembly") applies to the Tantra so-named, the assembly of deities in the maṇḍala described in this text, and sometimes to the maṇḍala's central deity. The Guhyasamāja Tantra was composed in India by the early eighth century. The earliest datable reference to the Tantra is in a text written by Amoghavajra, a Sogdian monk active in China, namely his Index of the Vajraśekhara Sūtra Yoga in Eighteen Sections (Jin-gang-ding yu-qie shi-ba-hui zhi-gui, T. 869), which he composed during the mid-eighth century. In it, Amoghavajra lists a text called the Guhyasamāja Yoga (mi-mi-hui yu-qie), his description of which is clearly identifiable with portions of the Tantra. Most likely the text at this period was somewhat shorter than the ultimate version, which was established by the late tenth century when it was translated into Chinese...