Fortress is a video game published by Strategic Simulations in 1983 for the Atari 8-bit computers and Apple II.

[4] The game takes place on a rectangular field, where two opposing players alternate turns.

If a new castle is built, it appears with four flags in each cardinal direction showing its zone of control.

When playing against the computer, there are five opponents to choose from: "The Squire" (beginner), "Lord Maginot" (the master of defense who will parry the player's moves), "Genghis Khan" (aggressive and strong), "Sir Galahad" (valiant but inexperienced), and finally "Count Vauban" (the most difficult).

"[4][5] In a review of the Atari 8-bit version for Antic, Edward Bever wrote, "Simple, fast, and well balanced, Fortress should appeal to anyone who enjoys a game that makes you think.