Most of the texts we study were written by shankara chari or commentaries. We can trace it back historically at least up to gora pada charia. There are names of gurus before gorapada charia also, but they are mythological thedo. You find their names in puranas and you cannot locate them in history exactly. But er, we're not going to go into the commentary directly, because then you tend to get bogged down. I want first of all to get the straight gets go straight to the heart of the openy shed with the help of the caricas.