In Europa Universalis II, Missions allow you to collect additional victory points on top of the ones you earn from battles, discoveries and economical gains. You can access the mission screen in-game from the information screen. Each mission has a time limit of 5 years. You will be penalized if you do not complete the mission within the limit. If you adjust your message settings to auto-pause popups related to completed/failed missions, the game will auto-pause every fifth year. This is a nice way to remember to adjust your dometic policy sliders every tenth year.