The ideal of a united Christendom continued to haunt the soul of France in spite of the predominating influence gradually assumed in French politics by purely national aspirations. From the reign of Charles VI, or even the last years of Charles V, dates the custom of giving to French kings the exclusive title of Rex Christianissimus. Pepin the Short and Charlemagne had been proclaimed "Most Christian" by the popes of their day: Alexander III had conferred the same title on Louis VII; but from Charles VI onwards the title comes into constant use as the special prerogative of the kings of France. Philippe de Mézières, a contemporary of Charles VI, wrote: "Because of the vigour with which Charlemagne, St. Louis, and other brave French kings, more than the other kings of Christendom, have upheld the Catholic Faith, the kings of France are known among the kings of Christendom as 'Most Christian'."
