In the early sixteenth century European monarchs and princes began relying on mercenaries, or professional soldiers, to fight in wars. This practice arose because military leaders had problems maintaining armies that were recruited from the peasantry. The mercenary system began in Italy in the 1300s and 1400s with condottieri, or contractors who hired soldiers. It then spread beyond the Alps into Germany and Switzerland.

Before mercenaries replaced traditional soldiers, all fit males between the ages of sixteen and sixty were legally eligible to serve in the army. When soldiers were needed the state sent captains to recruit in certain areas. This practice was common in Spain, for example, and gave the government control over the process. Men usually joined the army voluntarily, but military service was often required. Recruiting from the peasantry was not enough, however, because the system did not work properly. Perhaps one-fifth of eligible men avoided service by evasion, bribery, or legal challenge. As many as one-third of new recruits deserted before joining the main army. The situation was even worse once a campaign had started because 25 percent of soldiers usually deserted. At the end of a campaign, most soldiers were sent home. These dismissed soldiers, now unemployed and often penniless, were hated by the peasantry through whose land they had to pass. Some were unwilling to return home because they were not welcome. Overnight the former soldiers could become bandits who added to the already high level of violence in the countryside.

For these reasons military leaders preferred professional soldiers, who were more disciplined than untrained men. Some states placed permanent agents in certain regions to hire mercenaries. For example, Venice had agents who sought cavalry soldiers in Bosnia and pikemen (soldiers who carried spears with sharp points) in Switzerland. By the sixteenth century mercenaries were the mainstay of all armies. Although a hired soldier’s pay was often lower than that of a civilian job, mercenaries could become quite wealthy from looting enemy supply trains and conquered cities. In a society in which violence was common, an occupation that rewarded violence was probably appealing.