Release date: October 2001

Arriving more than five years after the release of Civilization II, Sid Meier's Civilization III introduced a number of new gameplay mechanics that remain features of Civilization games to this day. Strategically important resources, new civilization traits, and additional forms of government afforded leaders new ways to play, as did powerful civilization-specific units such as Egypt's War Chariots and France's Musketeers.

Assuming the role of one of 16 leaders from throughout history, players guided their chosen civilizations from 4000 BC into the near future, attempting to complete one of several paths to victory before the game ends in the year 2050. As in previous entries in the series, winning by being the first civilization to build a spaceship that reaches Alpha Centauri was an option, as was conquering all other civilizations.

Victory conditions introduced in Civilization III included using the new Culture system to assimilate other civilizations, employing Diplomacy to become the head of the United Nations, and controlling two thirds of the world's land and population. If none of these conditions were satisfied before the game ended, the player with the most points won. 

To succeed, players needed to balance technological advancement, access to important resources, and the desire for culture with the ongoing challenge of maintaining a good infrastructure and a military to defend it. In the years following the release of Civilization III, still more strategic considerations and ways to play were introduced in two expansions.

The first expansion for Civilization III, released in 2002, introduced several new game modes as well as support for online multiplayer. Eight more civilizations entered the fray as well, bringing with them powerful unique units including Korea's Hwacha siege weapon and the ax-wielding Viking Berserks. 

Civilization III: Play the World also added the Internet as a Wonder of the World, and unlocked fresh strategies for players with new civilization-agnostic units and tile improvements. These included Medieval Infantry and Guerillas, Civil Defense buildings, Airfields, Radar Towers, and more.

Civilization III: Conquests, released in 2003, introduced historical multiplayer scenarios designed to be completed in fewer turns than regular Civilization III campaigns. Featured scenarios included The Rise of Rome, Sengoku: Sword of the Shogun, WWII in the Pacific, and more.

Other new features in Conquests included eight more civilizations, additional government types, new Wonders of the World, more resources to collect, and the marsh and volcano terrain types. Experienced players looking for a challenge were also able to test their leadership skills at new Demigod and Sid difficulty levels that sat alongside the previous highest Deity setting.