During the 17th century, after the Thirty Years’ War, the Holy Roman Empire became far more decentralized than it had previously been. The Duchy of Brandenburg-Prussia, within the Holy Roman Empire, had been totally decimated by the war. This Duchy was in terrible condition when Frederick William inherited it in 1640. However, he inherited at an opportune moment because the kingdom of Sweden was overextended. In order to gain more power and land, Frederick William would need a large army. In order to maintain a large army, he would need money from taxes. He bribed the Junkers (local nobility) to approve his new taxes by offering to reduce the peasants to serfdom. Eventually, his army grew so large that he would no longer need to bribe the Junkers; he would only have to threaten them. The army grew to a whopping three percent of the population. Frederick William promoted religious toleration, and allowed people to come in to his territory who had been previously persecuted. He policy saw Brandenburg-Prussia thrive, and his actions allowed Prussia to be elevated to a kingdom under his successor, Frederick I.