Book excerpt: This 1955 work is the classic history of the development of modern diplomacy in Renaissance Europe. Sometime after the year 1400, the diplomatic traditions of civilized cultures-which have existed as far back as the records of human history extend-took a sharp turn that was the result of new power relations in the newly modern world. Mattingly believed these could be illustrative of how nations and traditions change...and that we might apply those lessons to our own rapidly changing global culture. Discover: [ the legal framework of Medieval diplomacy [ diplomatic practices in the 15th century [ the Italian beginnings of modern diplomacy [ precedents for resident embassies [ the dynastic power relations of European nations in the 16th century [ French diplomacy and the breaking-up of Christendom [ the Habsburg system [ early modern diplomacy [ and more. American scholar of European history GARRETT MATTINGLY (1900-1962) is also the author of Catherine of Aragon (1941) and the bestselling The Armada (1959), for which he won a Pulitzer Prize.