The development of the nation-state across Europe such as France and Belgium revolutionized politics and warfare. Key to the nation state was the ability of the king to centralize power and create a civil bureaucracy and professional military. These militarizes were expensive and war could easily bankrupt a country. To improve revenue the states developed methods to prevent local officials from gaining access to taxes. However, the most important steps were mercantilism, the national banks such as the Bank of England, and the introduction of parliaments. These parliaments were meant to integrate wealthy non-nobles, especially merchants, into the state’s political structure. A strong sense of self was also very important for these relatively small countries to maintain themselves and not simple disintegrate.