Eric Storey, Tiresias (from Metamorphoses)
In his Notes, Eliot tells us that the blind prophet Tiresias (one of the few voices to which a name is attached) is "the most important personage in the poem". He is at the centre of the work, figuratively and literally: a character who has been both man and woman in his long life, he is representative of all the other male and female voices in The Waste Land. He presides over the central scene of the poem, a loveless sexual encounter between a typist and her boyfriend. He is able to empathise with both, but looks down regretfully on a reiteration of all the other bad sexual experiences in The Fire Sermon. He has seen it all before.

Eliot helpfully points us to nineteen lines of (untranslated) Latin hexameter from Ovid's Metamorphoses:
  -Let’s be frank. You ladies enjoy it more than we men do. 
-Absolute rubbish, Juno replied. So they agreed to consult an expert, Tiresias: he had sexual experience from both perspectives. 
(The story goes that Tiresias had been walking in a green wood when he saw a pair of snakes mating; he separated them by smacking them hard with his walking stick. Miraculously, he was changed from man to woman, and remained female for seven years. Then he saw the snakes again, and thought, if a stroke of my stick was enough to cause a sex change, maybe the same thing will happen again… So he struck those self-same serpents with his stick and his manhood was restored.)
Tiresias, appointed umpire to the gods’ battle of the sexes, gave the thumbs-up to Jupiter; Juno took this decision very badly, to the point of irrationality: she cursed the referee with blindness. Gods can’t undo what other gods do, so Jupiter tried to make it up to Tiresias by giving him the power of prophecy.
Metamorphoses Book III, lines 318-336

There's more about Tiresias in The Waste Land here