Age of Empires Online is the next evolution in the best-selling real-time strategy (RTS) franchise Age of Empires. Developed by Microsoft Game Studios for the Games for Windows – LIVE platform, Age of Empires Online invites players to create a living, growing online world, shared with friends and friendly rivals around the world. Marrying fresh features with classic RTS gameplay, Age of Empires Online pays tribute to the original game while incorporating a new look, feel, and approach that appeals to long-time fans, newcomers, and everyone in between.
Age of Empires Online has been republished in mid-2017 under a non-commercial license under Microsoft's "Game Content Usage Rules" by an independent group of developers and can be played for free on a server emulator known as :Project Celeste" with all online features fully enabled. The team uses Microsoft's publicly released development-kit to balance, fix bugs, and expand the content where Microsoft's team left off.
The team behind Project Celeste have unveiled a total of 15 Player Vs. Player (Champion mode) rebalance patches, along with several questpacks. The latest, Realms of The World, features a whole new city and quest hub to visit. There has also been a handful of patches for the civilizations in PvE, and countless changes to maps and map consistency in both game modes. The community of Project Celeste feature many of the notable members of earlier-era AOEO Player Vs Player scene, as well as a few members of the competitive starcraft II scene.
The game can be played for free in single-player and multiplayer mode with all online features fully enabled. In May 2019, the team announced that they are developing Microsoft's unreleased Roman civilization for play based upon all known data of the civilization before the official servers were closed. It was finalized and released on March 14th, 2021