Power

The Power level of your land is determined by the combined power level of your units. Archers, Axemen, and Spearmen are all worth (x) base power, with Horsemen being worth (x) base power.

Upgrades change the power value of these units.

Sergio's comment
"Power depends on basic power of a unit (with horsemen being about twice as powerful as others), their level and related upgrades." (May 18, 2016)