His two great masters of war, foreigners in origin like himself, were Belisarius the Thracian and Narses the Armenian. Africa was wrested from the Vandals; Italy from the successors of Theodoric; and much of Spain from the Western Goths. Under Justinian the Byzantine or Eastern Empire resumed much of the majesty and power of ancient Rome. But the crowning glory of his career was the Code. One of the greatest historians says of his reign: "Its most instructive lesson has been drawn from the influence which its legislation has exercised on foreign nations. The unerring instinct of mankind has fixed on this period as one of the greatest eras in man's annals." The Code was a digest of the whole mass of Roman law literature, compiled and annotated at the command of Justinian, under the supervision of the great lawyer Tribonian, who, with his helpers, reduced the chaotic mass to a logical system containing the essence of Roman law. The first part of the _Codex Constitutionem_, prepared in less than a year, was published in April, 529. The second part, the _Digest_ or _Pandects,_ appeared in December, 533. To insure conformity, both were revised and issued in November, 534, the Institutiones, an _elementary_ text-book, founded on the _Institutiones_ of Gaius, who lived A.D. 110-180, being added, and the whole, as a complete body of law, given to the law schools at Constantinople, Rome, Alexandria, Berytus, and Caesarea, for use in their graduate course. Later the _Novellae Constitutione_, or _Novels,_ most of them in Greek, comprising statutes of Justinian arranged chronologically, completed the Code. Forgotten or ignored during the lawless days of the Dark Ages, an entire copy of this famous code was discovered when Amalphi was taken by the Pisans in 1137. Its publication immediately attracted the attention of the learned world. Gratian, a monk of Bologna, compiled a digest of the canon law on the model of that work, and soon afterward, incorporating with his writings the collections of prior authors, gave his "decretum" to the public in 1151. From that time the two codes, the civil and canon laws, were deemed the principal repositories of legal knowledge, and the study of each was considered necessary to throw light on the other.