***Note: This is an expansion you need Settlers of Catan to play this.
Dark clouds are gathering over the peaceful island of Catan. Wild barbarians, attracted by the wealth of Catan, sailed to attack the country.
Fortunately, warning has given Catan time to meet the danger. The size of the barbarian army corresponds to the number of cities in Catan. Thus, for Catan to fend off the barbarian attack, the players must form a knight force as strong as the barbarian force.
In addition to fending off the barbarians, players compete to build the three great metropolises of Catan. Each of these magnificent centers are worth two additional victory points. To build a metropolis, players must invest in city improvements. To acquire these improvements, players must acquire the three new types of Trade Cards: Coinage, Paper, and Cloth. These cards can only be gained by building a city next to mountain, forest, or pasture hexes.
4th Edition FAQ on the Mayfair site, follow this link.
Catanians who enjoy the variability and interactivity of Settlers, but who want to expand on the strategic possibilities, will want to add Cities & Knights to their library. Players must spend resources to hire and feed knights that defend the island, lest their cities be razed to the ground by advancing Barbarians. The cities, meanwhile, now generate commodities as well as resources; these commodities build city improvements which, in turn, provide additional powers, plus access to the three Progress Decks that have replaced the original Development Cards. Players will soon discover that Cities & Knights opens the door to much more aggressive, crush-your-enemies tactics than the original Settlers; though trading is still critical, so it's best not to smite your opponent too heartily.