LAW - Rules established by a governing authority to institute and maintain orderly coexistence.
LAW - A rule or body of rules of conduct inherent in human nature and essential to or binding upon human society.
LAW - A rule of conduct established and enforced by the authority, legislation, or custom of a given community, State, or nation.
LAW - A rule of human conduct, imposed upon and enforced among the members of a given state.
LAW - A rule of conduct or procedure established by custom, agreement, or authority.
LAW - The body of rules and principles governing the affairs of a community and enforced by a political authority; a legal system.
LAW - A set of rules or principles dealing with a specific area of a legal system.

In the Middle Ages, law was considered to have been dictated by Divine Will, and revealed to wise men. The most ancient legal precedents and customs were considered to be the best law, and much of Continental Europe wound up modeling secular law after the old Roman law. In Byzantium, secular and sacred law were somewhat intermingled, with secular law taking precedence. In Western Europe, however, religious and secular law were separate bodies. Church law was known as Canon Law, and applied to the clergy, to the secular world in matters of the administration of the Sacraments such as marriage, and to the immunity of the clergy from secular law. This is the root of the conflict between Church and State. St. Augustine arranged law thru three levels:

Divine law, a perfect system comprehended thru faith and reason;
Natural law, which could be understood by all creatures, lacked the perfection of faith, and could be improved by philosophy;
Temporal (secular) law, obedience to which was enjoined on all Christians, save where it conflicted with Divine or Canon law.