In 1415 Henry V, king of England, invaded northern France. In the east, two new powers, Muscovy and, above all, the Ottoman Empire, were putting eastern Europe to the sword. The 'modern states' of western Christendom were characterised by the provision of substantial revenues derived from national taxation raised by consent. Dialogue, political intercourse between prince and subjects, was essential to the modern state. Both theory and practice needed adapting to the particular political society of each state on at least two levels. Epitomising power, witnessed by an attentive audience, they became complex rituals, given tangible expression as dramatic presentations overlaid with symbolism. Speeches, in particular sermons, could convey unequivocal declarations of political thought. Clerics and ecclesiastics who had completed their university studies in the faculty of arts had become acquainted with the political works of Antiquity. History, like politics, was being transformed by literature; the success of Jean Froissart's work in aristocratic and bourgeois circles is testimony of this.