VASSALS
Vassals are soldiers that serve a liege lord for a fixed term each year in exchange for a farm, not for cash. A character who establishes a stronghold can parcel out land to settlers for vassal service.
A knight-vassal is granted at least 1 square mile of land and 50 peasants as tenants by his lord. Those 50 peasants don't pay taxes to the lord, instead they “pay” 2gp each per month each in labor as rent to the knight. That yields the knight 1200gp per year and a home that grants him half maintenance costs for himself and his squire, and any soldiers or mooches that will fit into his house. In return, the knight must serve his lord for 2 months a year without pay. During such service he must be fully equipped in plate, shield, lance and sword, with a heavy warhorse and a mounted squire and a spare horse.
Lesser fighting vassals can also be established. A half-mile grant and 25 peasants might be a vassalage for a medium or light horseman, a quarter-mile grant might be a vassalage for an archer or heavy infantry vassal.
A peasant militia can also be assembled to fight in defense of the home-fief only, typically these are unpaid, but can't be moved away from their home village area. These militia can be well or poorly armed depending on the stornghold area.