An Event is an encapsulated set of choices and effects which take place outside of the normal interaction of other elements of the game. Events are used primarily to apply the effects of historical events within the game. Some automatically occur at specified times or upon other prerequisites. Other events are more random. Some are extremely specific and detailed, while others are generic. Some involve interaction with the affected nations, while others simply occur without interactive choices being presented.
While playing, events which happen to the active nation will pop up in a box. Many will include explanatory text and offer the player with a choice. Effects of the choices can often be seen by resting the cursor over the button, revealing a tool tip with a list of game effects.