Initially, the decay of primary group solidarity within the leading cities of Italy and of the town militias which were its military expression invited chaos. Armed adventurers, often originating from north of the Alps, coalesced under informally elected leaders and proceeded to live by blackmailing local authorities, or, when suitably large payments were not forthcoming, by plundering the countryside. Such “free companies” of soldiers became more formidable as the fourteenth century [C.E.] advanced. In 1354, the largest of these bands, numbering as many as 10,000 armed men, accompanied by about twice as many camp followers, wended its way across the most fertile parts of central Italy, making a living by sale and resale of whatever plunder the soldiers did not consume directly on the spot. Such a traveling company was, in effect, a migratory city, for cities, too, lived by extracting resources from the countryside through a combination of force or threat of force (rents and taxes) on the one hand and more or less free contractual exchanges (artisan goods for food and raw materials) on the other.
The spectacle of a wealthy countryside ravaged by wandering bands of plundering armed men was as old as organized warfare itself. What was new in this situation was the fact that enough money circulated in the richer Italian towns to make it possible for citizens to tax themselves and use the proceeds to buy the services of armed strangers. Then, simply by spending their pay, the hired soldiers put tax monies back in circulation. Thereby, they intensified the market exchanges that allowed such towns to commercialize armed violence in the first place. The emergent system thus tended to become self-sustaining. The only problem was to invent mutually acceptable contractual forms and practical means for enforcing contract terms.
From a taxpayer’s point of view, the desirability of substituting the certainty of taxes for the uncertainty of plunder depended on what one had to lose and how frequently plundering bands were likely to appear. In the course of the fourteenth century, enough citizens concluded that taxes were preferable to being plundered to make the commercialization of organized violence feasible in the richer and better-governed cities of northern Italy. Professionalized fighting men had precisely parallel motives for preferring a fixed rate of pay to the risks of living wholly on plunder. Moreover, as military contracts (Italian condotta, hence condottiere, contractor) developed, rules were introduced specifying the circumstances under which plundering was permissible. Thus, in becoming salaried, soldiering did not entirely lose its speculative economic dimension.
— The Pursuit of Power, pp. 73-74