What subject did Professor Albus Dumbledore teach when he was recruited as a teacher in Hogwarts. Also, till his death, what other subjects did he teach.
He was a Transfiguration teacher. From Chamber of Secrets, Tom Riddle tells Harry:
'Only the Transfiguration teacher, Dumbledore, seemed to think Hagrid was innocent. He persuaded Dippet to keep Hagrid and train him as gamekeeper. Yes, I think Dumbledore might have guessed. Dumbledore never seemed to like me as much as the other teachers did...' (CHAPTER SEVENTEEN, The Heir of Slytherin)