The Collector is an Elder of the Universe and has lived for over five billion years. The longevity of the Elders is based on their particular obsessions and the Collector keeps himself occupied collecting artifacts and things of his interest across the universe.
Taneleer Tivan, the Collector, began collecting heroes in Avengers #28 (March 10, 1966).
The Avengers #28 – Among Us Walks… a Goliath released by Marvel
When the Wasp goes missing Hank Pym turns to the Avengers, and to mark his return he dons a new costume and calls himself Goliath. Little does the team know the Collector wants to add them all to his collection and has enlisted the Beetle into helping him accomplish this task.