Warrior (Civ4)/Civilopedia

The earliest military forces were simply the citizens of the city, armed with whatever implements they could use as weapons. Although a militia made out of warriors was inexpensive, they were no match for organized armies. Warriors were usually used as stopgap measures while waiting for superior units to be trained, or to defend a city that had been temporarily cut off from military support. In a crisis situation, an assembly of warriors is better than no defense at all.