Diplomacy
the science or art of conducting negotiations, arranging treaties, and carrying on other important business, between nations; the branch of knowledge which deals with the relations of independent states to one another, the agency or management of envoys accredited to a foreign court; the forms of international negotiations. The Cardinal de Richelieu is is generally considered as the founder of that regular and uninterrupted intercourse between governments which exists at present between almost all the Christian powers. Diplomatic agents are of several degrees: (1) ambassadors; (2) envoys extraordinary and ministers plenipotentiary; (3) ministers resident; (4) chargés d'affaires; (5) secretaries of legation and attachés. Their rank was regulated in Europe in the above order, by the Congress assembled at Vienna in 1814.