Welcome to Age of Empires II: HD Edition - The Forgotten; the first new official expansion for the Age of Empires II universe in over ten years. Challenge friends with five additional civilizations and technologies, battle through four campaigns, vanquish opponents in new game modes on massive maps, or shoutcast a match and stream it all through twitch.tv. Crafted exclusively for Age of Empires II: HD Edition; The Forgotten expansion builds upon the Age of Empires II: HD experience and includes Steam workshop support, new expansion rankings, steam trading cards, and more!

Age of Empires II: The Forgotten is the second official expansion pack for Age of Empires II. It features five new civilizations, (the Incas, Indians, Italians, Magyars and Slavs), new units and technologies, new maps, enhanced AI, a higher population limit, greater on-screen rendering, bug fixes and several tweaks to old units, technologies, and bonuses for improved gameplay balance.

Originating as a fan-made modification (before they became Forgotten Empires Studios) entitled Age of Empires II: The Forgotten Empires, the expansion was developed with SkyBox Labs and released in 2013 exclusively on Steam. It requires the Age of Empires II HD Edition for installation.