This unit is usually vital in early gameplay, and can be built after researching just three advances, Alphabet, Masonry, and then Mathematics. With an attack rating of 6 it can overcome most defensive units of the same era quite frequently. They can also be used defensively in cities, to activate when a city is threatened by attacking nearby units. Used in combination with more mobile units, such as chariots or cavalry, they present a tremendous threat in early game to any city. Furthermore, they are very cheap to build, and can be produced en-masse quite rapidly.