The Empire which collapsed in 476 left a rich legacy of economic and social thought which survived its political structure and remained untouched by historical accident. This inheritance consisted primarily of moral principles, derived from the Gospels and defined by the Fathers, and of habits of thought formed in the Roman world.

In East and West alike, Christianity had flowered among peoples accustomed to certain economic and social institutions deemed natural or commonly accepted and regulated by laws: for example, property and slavery. It did not reject outright the learned or popular view of these traditional institutions, but it introduced a conception of man and of human relationships which modified and threatened existing customs and, indeed, the very foundations of society. By their commentaries upon the Scriptures, by their enlargements upon precepts and counsels, the Doctors, and especially Ambrose and Augustine, established the whole programme of a new system of ethics, the fiats and the interdicts of which were already sanctioned by popes and councils.

Thus, as early as the end of the fifth century, the fundamental conceptions about economy and society had been enunciated in Christian literature and in the imperial legal codes. The barbarian and feudal periods were to do no more than preserve this accumulated wealth of ideas, which came to sudden fruition at the time of the twelfth-century renaissance and the scholastic period.

In a broad introduction we shall trace the external history, as represented by the environment and sources; then consider successively the conceptions of economy and of society before summing up, in conclusion, the principal repercussions of these conceptions upon the practice of nations.