The Cities and Knights of Catan Expansion Pack is made to be used with the original Settlers of Catan board game.  The original game allows for four players, with the expansion pack, up to six players can participate.  The Cities and Knights expansion can be used with the Seafarers expansion and the original game creating  additional complexity and interest for the game.

The Cities and Knights Expansion pack contains 1 barbarian tile, 36 commodity cards, 54 progress cards, 6 defender of Catan Victory Point cards, 4 development flip charts, 12 city walls, 24 knights, 3 metropolis pieces, 3 metropolis tokens, 1 barbarian ship, 1 merchant, 1 event die, games rules and almanac.

There is some controversy among players regarding this expansion pack.  Some players feel it adds too much complexity to the original game and makes it too long.  Others enjoy the additional complexity and don't mind the longer playing time.

The commodities cards can be exchanged for two different resource cards and can be used to upgrade their cities or to trade with other players like resource cards.  They can also be stolen by the robber.

 Each player receives three city walls at the beginning of the game.  The walls can be added to by paying two bricks.  The walls allow players to increase their hand limit to 11 cards when a robber is rolled, but overall don't change the basic game much.

The knights present the biggest change in the strategy of the game.  Each player receives 6 knights at the beginning of the game.  Knights can be activated and placed at any intersection built by the player. Knights have a black and white sticker on one side and a color sticker on the other which are used to indicate if the knights are active or inactive.  One wool and one ore activates a basic knight, one wool and one ore upgrades a basic knight to a strong knight. An additional wool and ore upgrades a strong to a mighty knight.  A knight can take over an occupied intersection if he is stronger than the occupying knight.  An inactive knight can be activated for one grain.  This increases the value of the grain resource.  Knights can stop players from building past them.  Knights add a lot more strategy to the basic game.

Barbarians arrive on a ship. The ship counter is on an eight space track and once it is moved to the last space on the track, the barbarians attack.  The strength of the barbarians is equal to the number of cities owned by all the players.  The barbarian attacks have the most effect on the weakest players.

There are more components to this expansion pack and it makes the game far more interesting and complex than the basic game.  The addition of the knights creates more opportunity for strategy against  opponents both by blocking them from building cities and settlements and by defending against the barbarians.  Overall most players, especially advanced players, like this expansion pack a lot.