Who taught Voldemort?

[Valy]

No: HPFGUIDX 130561

This is a little question that suddenly popped up in my brain:

Who taugh Voldemort the AK and Cruciatus Curse when he graduated out from
Hogwarts?

We know he is a powerful wizard, have created incredible curses and hexes,
but well... I think the AK curse is much older than Voldie himself.
And I dont think they taught unforgivable curses at Hogwarts, unless the
headmaster and some teachers were into Dark Arts... (Phineas Nigellus
anyone?)
Or his friends at Hogwarts, into the Dark Arts, taught him between classes
(despite he was incredibly talented to begin to call himself as "Lord
Voldemort"), since he was locked into a muggle orphanage while holydays
until he became adult?

Valy.