The Marathon trilogy refers to the set of three games released by Bungie that depict events occurring within the Marathon universe. The three games are Marathon 1, Marathon 2: Durandal, and Marathon Infinity.
- Main article: Marathon 1
Marathon 1 was released in 1994.
Marathon 2: Durandal
- Main article: Marathon 2
Marathon 2 was released in November, 1995.
- Main article: Marathon Infinity
Marathon Infinity was released in 1996. It was co-developed by Bungie and Double Aught Studios. Marathon Infinity reused the engine designed for Marathon 2: Durandal, but added a completely new single-player scenario, two new weapons, and came with Anvil and Forge.