(a) Historical. In very early times special privileges were extended to heralds, ambassadors, or other bearers of the state will. Laws[205] and history record as a fact this practice which had long been observed. The ambassador was often one who in his own state held some priestly office. In the days of the Roman dominance, the office of ambassador was commonly exercised by one holding a religious office, and while the unity represented by the church remained prominent, its officials were often ambassadors. Both from necessity and from the sacred character of the person, the ambassador was usually regarded as inviolable. The person of the ambassador was respected long before there was any recognition of the rights and dignity of states as states. In order that there might be any such intercourse, it was necessary that the agents should not be placed in undue personal peril.[206]
With the preëminence of the Italian city states in the Middle Ages there came the development of diplomacy as an art. The most distinguished men of the times were called to this state service. Machiavelli's name is inseparably linked to one school of diplomacy. Dante, Petrarch, Boccaccio, and others whose names have become famous, were sent on missions.[207]
During the thirteenth century, Venice outlined the policy which her ambassadors should follow, and there the system of foreign representation became well established. This system included the granting of a commission, instructions, letter of credence, attachés, etc. Italy may, indeed, be called the home of the diplomatic system.
For many years, in fact till comparatively recent times, ambassadors were looked upon with suspicion, as spies whom monarchs were more willing to give than to receive. Gradually, however, the practice of sending and receiving ambassadors was seen to have much value. During the fifteenth century, which marks the beginning of the modern period in the history of diplomacy, the practice of sending permanent ambassadors seems to have arisen. There may have been isolated cases of sending of permanent ambassadors before this time, but from the fifteenth century the practice became more and more common, though the different countries did not observe any uniform regulations as to personnel, procedure, or in other respects. From this time diplomacy became more of a career, and one going on a mission to a foreign country received careful preparation that he might outwit the representatives of the state to which he was sent. Sir Henry Wotton's oft-quoted definition of an ambassador, "An ambassador is an honest man, sent to lie abroad for the good of his country,"[208] describes the attitude taken in many countries toward the office, when early in the seventeenth century he wrote the definition in Christopher Flecamore's album. Gradually the rules of international negotiation became established, and treatises upon the subject appeared.
The Peace of Westphalia in 1648, which marks the beginning of modern international relations, showed that modern diplomacy had already obtained a recognition, and served to give it a more definite form. This date serves as a boundary to the first division of the modern period in the history of diplomacy. The years from the early part of the fifteenth century to the Peace of Westphalia are the years of beginnings. From this time the system of permanent ministers, which so greatly changed the character of international negotiations, became almost a necessity through the development of the equilibrium of the states of Europe.[209]
During the years 1648 to 1815 the relations of states became more complex, and the business of international negotiation more delicate. Diplomatic practice, always tending to look to precedent, suffered severe strains under the ambitious monarchs occupying the thrones of Europe after the Peace of Westphalia. Principles and precedent were often disregarded to obtain political ends. So great was the friction that at length some of the more commonly disputed questions were settled at the Congress of Vienna, 1815.
(b) The question of relative rank of state agents gave rise, in the days before the Congress of Vienna, to many difficulties. The protocol of that Congress of March 9, 1815, together with the eighth article adopted at the Congress of Aix-la-Chapelle, Nov. 21, 1818, give the basis of present practice as follows:—
"In order to prevent in future the inconveniences which have frequently occurred, and which may still occur, from the claims of Precedence among the different Diplomatic characters, the Plenipotentiaries of the Powers who signed the Treaty of Paris have agreed on the following Articles, and think it their duty to invite those of other Crowned Heads to adopt the same regulations:—
Division of Diplomatic Characters
Art. I. Diplomatic characters are divided into Three classes: That of Ambassadors, Legates, or Nuncios.
That of Envoys, Ministers, or other persons accredited to Sovereigns.
That of Chargés d'Affaires accredited to Ministers for foreign affairs.