Age of Empires II is a real-time strategy game centered on raising towns, gathering resources, and building armies to crush your rivals. Players guide one of 13 civilizations through four Ages — the Dark Age, the Feudal Age, the Castle Age (the High Middle Ages), and the Imperial Age (echoing the Renaissance) — spanning a thousand years of history. Each new Age unlocks fresh units, structures, and technologies, but advancing requires first raising certain buildings of the current Age and then paying a price in resources, typically food and gold.