BBEGINNING IN THE ELEVENTH CENTURY, rulers in some parts of Europe began to manipulate existing institutions to build up their power, becoming kings over growing and slowly centralizing states. As rulers expanded their territories and extended their authority, they developed larger bureaucracies, armies, judicial systems, and other institutions of state to maintain control and ensure order. Because these institutions cost money, rulers also initiated systems for generating revenue and handling financial matters. Some rulers were more successful than others, and the solutions they found to these problems laid the foundations for modern national states.