books.google.com - Though many historians date the practice of diplomacy to the Renaissance, Pierre Chaplais shows that medieval kings relied on a network of diplomats and special envoys to conduct international relations. War, peace, marriage agreements, ransoms, trade and many other matters all had to be negotiated....http://books.google.com/books/about/English_Diplomatic_Practice_in_the_Middl.html?id=pR58WnXzh-wC&utm_source=gb-gplus-shareEnglish Diplomatic Practice in the Middle Ages
