The Kingdom of Bohemia was a kingdom that covered the Czech part of the European region of Bohemia. Its capital was Prague. Form 1526, it formed the northwestern part of the lands of the Habsburg Monarchy. The kingdom started in the 12th century, and was part of the Holy Roman Empire, while it existed. In total, there were 37 monarchs. Most were from the House of Habsburg. The kings were often in a personal union. The king was also a Margrave of Moravia and a Duke of Silesia.