ABSTRACT
The second half of the fifteenth century saw a number of important changes in the western European state system, and the political units which emerged from them were to remain the principal forces in diplomacy until Italy and Germany were unified in the nineteenth century. As so often at this period, however, Italian politics lay at the heart of European diplomacy, and it was this which gave Henry his opportunity for war. Whereas in 1378 the political alignments of the Anglo-French War had played a vital part in determining the lines of obedience in the Great Schism, a century later England was more liable to be tossed about in the diplomatic crosscurrents which flowed from the enmities of more powerful countries. Henry's allies, however, who had been keeping open alternative political options, found these preferable, and were quite prepared to pull out of the alliance almost as soon as it was signed.
