While a revolution is taking place, all other regions the faction controls are greyed out, do not generate revenue, and cannot be controlled until the revolution is put down or succeeds. If the side they choose loses, the game is automatically over. If a revolution occurs, the player is given the choice of siding with the rebels or with the government. Revolutions are the only way factions can change their government type. Depending on the class that rebelled and the government type, revolutions may also change government type (listed below). Certain units that are unique to a certain government type (such as Republican Guard for republics and Garde du Corps for absolute and constitutional monarchies) automatically disband if a revolution succeeds. If successful, revolutions depose the current government (including the leader of the nation and the entire cabinet) and replaces it with a randomly generated cabinet. In this sense, they are similar to Rebellions, except that it only takes place in the faction's home region. Revolutions occur when a class in the home region of a faction has negative public order (signifying dissatisfaction with the current government) for three consecutive turns, spawning a rebel army, which will try to take the region capital. In Empire: Total War, revolutions are rebellion against a government.
Revolutions are defined as an action usually undertaken by people who desire drastic change. A revolution is an event in Empire: Total War.