Tchaikovsky was an enthusiastic student at the St. Petersberg Conservatoire. Anton Rubinstein asked Tchaikvosky to write a series of contrapuntal variations on a given theme. "I expected that he would present me with about a dozen. But Tchaikovsky turned up the next class day with more than two hundred!"
Cited in: Hanson, Lawrence and Elisabeth (1965) Tchaikovsky: A New Study of the Man and His Music. London: Cassell & Company, p.62.