After playing a tile with a cloister (monastery in 2014 edition) in it, a player may place a follower on it as a Monk. When the game ends or the cloister is completely surrounded on all eight sides, the player with the follower on the cloister gains one point for the cloister, and an additional point for each adjacent tile. Three types of follower can be placed as a monk, the Normal Follower and the Wagon are the most common unless the Count of Carcassonne expansion is played, in which case the Big Follower is more likely to be played which is worth two followers.
Note: some versions of the rules refer to the Cloister as a Monastery. The terms are interchangeable.