 Charles V revitalized the medieval concept of the universal monarchy and spent most of his life defending the integrity of the Holy Roman Empire from the Protestant Reformation, the expansion of the Ottoman Empire, and a series of wars with France.With no fixed capital city, he made 40 journeys, travelling from country to country, and it is estimated that he spent a quarter of his reign on the road.The imperial wars were fought by German Landsknechte, Spanish tercios, Burgundian knights, and Italian condottieri.