(a) Greece. The dispersion of the Greeks in many colonies which became practically independent communities gave rise to systems of intercourse involving the recognition of general obligations.[18] The maritime law of Rhodes is an instance of the general acceptance of common principles. The main body of this law has not survived, yet the fragment appearing in the Digest, De Lege Rhodia de Jactu,[19] is, after more than two thousand years, the basis of the present doctrine of jettison. It is reasonable to suppose that though the words of other portions of the Rhodian law are lost, the principles may have entered into formation of later compilations. The recognition by Greece of the existence of other independent states, and the relations into which the states entered, developed crude forms of international comity, as in the sending and receiving of ambassadors[20] and the formation of alliances.[21]
(b) Rome. Rome made many contributions to the principles of international law in the way of the extension of her own laws to wider spheres, and in the attempt to adapt Roman laws to conditions in remote territories. In this early period Rome may be said to have contributed to the field of what is now considered private international law rather than to that of public international law. This is evident in the laws in regard to marriage, contract, property, etc. The dominance of Rome impressed her laws on others, and extended the influence of those principles which, from general practice, or conformity to accepted standards, gained the name Jus Gentium.[22]
[§ 11. Middle Period]
The varied struggles of the middle period—from the beginning of the Christian Era to the middle of the seventeenth century—had a decided influence upon the body and form of international law.
(a) Roman Empire. The growth of the Roman Empire, as the single world power and sole source of political authority, left small need of international standards. The appeal in case of disagreement was not to such standards, but to Cæsar. The idea of one common supremacy was deep-rooted. Political assimilation followed the expansion of political privileges.
(b) The Church. A similar unifying influence was found in the growth of the Christian Church which knew no distinction—bond or free, Jew or Gentile. Christianity, called to be the state religion early in the fourth century, modeled its organization on that of the Roman Empire; and from the sixth century, with the decay of the Empire, the Church became the great power. The belief in the eternity and universality of Roman dominion was strengthened by the Church, although materially changed in its nature.[23] Whatever the inconsistencies in Church and State during the first ten centuries of our era, there had grown up the idea, of great importance for international law, that there could be a ground upon which all might meet, a belief which all might accept, both in regard to political and religious organization. For five hundred years before the days of Boniface VIII. (1294-1303), the holder of the papal office had from time to time acted as an international judge.
The canon law, codified by Gregory IX. (1227-1241), was planned to rival the Corpus Juris Civilis. The Popes, with varying degrees of success, tried to render such international justice as the discordant elements introduced by the growth of cities and rise of nationalities demanded.[24] From the Council of Constance (1414-1418), which was a recognition of the fact of nationality, and at which the emperor for the last time appeared as the great international head, the decline of both the Church and the Empire as direct international factors was rapid.
(c) Feudalism. By the eleventh century feudalism had enmeshed both the temporal and spiritual authorities. This system, closely related to the possession of land and gradation of classes, discouraged the development of the ideas of equality of state powers necessary for the development of international law, though it did emphasize the doctrine of sovereignty as based on land in distinction from the personal sovereignty of earlier days.
(d) The Crusades (1096-1270), uniting Christendom against the Saracen for foreign intervention, awakening Europe to a new civilization, expanding the study and practice of the Roman law which feudal courts had checked, weakening many feudal overlords, enfranchising towns, freeing the third estate, spreading the use of the Latin language, enlarging and diversifying commerce, teaching the possible unity of national interests, led to the apprehension of a broader basis in comity which made the growth of interstate relations more rapid.[25]
(e) Chivalry. The code of chivalry and the respect for honor which it enjoined introduced a basis of equable dealing which on account of the international character of the orders of chivalry reacted upon state practice throughout Christian Europe.