0 A.D. is described as 'free, open-source, cross-platform real-time strategy (RTS) game of ancient warfare. In short, it is a historically-based war/economy game that allows players to relive or rewrite the history of Western civilizations, focusing on the years between 500 B.C. and 500 A.D'. There are more than 25 games similar to 0 A.D. for a variety of platforms, including Windows, Linux, Mac, Steam and Wine. The best alternative is Age of Empires. It's not free, so if you're looking for a free alternative, you could try Starcraft or openage. Other 0 A.D. like games are Warcraft III (Paid), Stronghold (Paid), Widelands (Free, Open Source) and Age of Mythology (Paid).
Historically accurate campaigns and realistically recreated battles where you can manage up to 8,000 units on the field at once. Cossacks Anthology includes: Cossacks: European Wars, Cossacks: The Art of War, and Cossacks: Back to War.
Savage2 combines real time strategy and first person action in one fluid game. Instead of sending mindless computer drones into battle, imagine organizing real human players on a crusade to conquer your adversary.
Dominus is a free multiplayer browser strategy game. Grow in power by conquering other player's castles and making them your vassal. Vassals send their lord part of their income. Make everyone in the game your vassal to become the Dominus.
Europa 1400: The Guild (also titled Europa 1400 or The Guild) is a simulation game set in Europe from the year 1400 up to 1815. In it, the player tries to guide a family dynasty to power and wealth, starting from one character of limited means. Represent entire series of Europa 1400: The Guild games.
Imperial Domination II is a turn-based strategy game, set after the conquests of Alexander the Great and before the rise of the Romans. Expand your empire by trade, diplomacy, knowledge or just brute force. It's up to your to decide the fate of Europe. Represent entire series of Imperial Domination games.