Two big drivers of some of the bloodiest wars the world has seen were Conspicuous Consumption and Work Ethic. War was partly a commercial venture. Having lost the Crusades (1095-1291), a series of 'internal' Christian wars raged between 1522 and 1700. Leaders craving power used powerful stories to create angry bases to further their interests. Conspicuous Consumption is spending money on luxury goods and services, to publicly display wealth and power. Work Ethic is the belief that hard work and diligence have an innate moral benefit. When lots of people are poor and struggling, it can't be hard to get people angry by pointing at people who aren't working as hard, and yet are displaying their wealth. Indulgences (a payment to reduce the punishment for sins) were used to finance buildings such as St. Peter's Basilica. The German Monk, Martin Luther asked, "Why does the pope, whose wealth today is greater than the wealth of the richest Crassus, build the basilica of St. Peter with the money of poor believers rather than his own money?".