Sri SinghaAlso: Sri Sinha, Shri Singha, Sri Simha
An Indian teacher of whom no dates are known. He is said to have received his initiation into the Nyingtig teachings from Manjusrimitra, another early adept with an uncertain biography. The problem here is that Sri Singha is regarded as the teacher of people who lived more than 200 years apart in time (see Jnanasutra); a feat rather unlikely even for an accomplished master of secret (alchemical/sexual) Tantra.
What is certain, however, is the fact that all lineages of the Innermost Essence are based in the work of Sri Singha (Four Cycles of Nyingtig) and reached Tibet by way of his 8th century successors (said to have been personal disciples) Padmasambhava and Vimalamitra and through a group of 25 Tantras given by Sri Singha to his student Vairocana.