law book, also formed the basis for much of the Fetha Negest, which remained in force in Ethiopia until 1931. In the West In the west, Justinian's political authority never went any farther than certain portions of the Italian and Hispanic peninsulas. In Law codes issued by the Germanic kings, however, the influence of early Eastern Roman codes on some of these is quite discernible. In many early Germanic states, Roman citizens continued to be governed by Roman laws for quite some time, even while members of the various Germanic tribes were governed by their own respective codes. The Codex Justinianus and the Institutes of Justinian were known in Western Europe, and along with the earlier code of Theodosius II, served as models for a few of the Germanic law codes; however, the Digest portion was largely ignored for several centuries until around 1070, when a manuscript of the Digest was rediscovered in Italy. This was done mainly through the works of glossars who wrote their comments between lines (glossa interlinearis), or in the form of marginal notes (glossa marginalis). From that time, scholars began to study the ancient Roman legal texts, and to teach others what they learned from their studies. The center of these studies was Bologna. The law school there gradually developed into Europe's first university. The students who were taught Roman law in Bologna (and later in many other places) found that many rules of Roman law were better suited to regulate complex economic transactions than were the customary rules, which were applicable throughout Europe. For this reason, Roman law, or at least some provisions borrowed from it, began to be re-introduced into legal practice, centuries after the end of the Roman empire. This process was actively supported by many kings and princes who employed university-trained jurists as counselors and court officials and sought to benefit from rules like the famous Princeps legibus solutus est ("The sovereign is not bound by the laws", a phrase initially coined by Ulpian, a Roman jurist). There are several reasons that Roman law was favored in the Middle Ages. Roman law regulated the legal protection of property and the equality of legal subjects and their wills, and it prescribed the possibility that the legal subjects could dispose their property through testament. By the middle of the 16th century, the rediscovered Roman law dominated the legal practice of many European countries.