" Fighting and obtaining wealth were inseparable and interconnected: freed from the need to engage in productive work, the nobility had the leisure to cultivate their martial skills.84 They certainly fought for honor, glory, and the sheer pleasure of battle, but warfare was, “perhaps above all, a source of profit, the nobleman’s chief industry.”85 It needed no justification, because its necessity seemed self-evident. "
― Karen Armstrong , Fields of Blood: Religion and the History of Violence