Britannia is a game for three, four, or five players. It broadly depicts wars in, and migrations to, Britain in the centuries from 45 AD to 1085 AD, from the Roman invasions to the Norman Conquest. Each player controls several tribes or nations. Nations gain victory points in a variety of ways, such as by occupying specified areas on the map at specified times. Each nation consists of several playing pieces, most of them armies; the player moves these on the map, and with them he may attack pieces controlled by other players. Such battles are resolved with the aid of dice. Nations acquire additional pieces through natural increase in population and through reinforcements from their homelands across the sea. Each turn represents 75 years, except for the last four turns which represent shorter periods. At the end of the 16 turns the player whose nations have accumulated the largest number of victory points wins the game. The standard game takes up to four hours, while the short three player game takes about two hours. The four player game is recommended as providing the best combination of player interest, interaction, and overall game balance.