The beginning of jurisprudence is usually attributed to the 11th–12th centuries, when the school of glossators created a general, scholastic-based methodological approach to the study and teaching of the Roman law. This textualistic method was later transformed by the so-called school of “commentators”, especially Bartolo da Sassoferrato. The commentators, unlike the glossators, were much more interested in particular public law questions. Mainly this interest was dictated by the political situation, including the threat to the autonomy of Italian cities. Nevertheless, a fundamental revision of the glossators’ method became possible only later, when, under the influence of humanist criticism, the idea of the historical-philological method spread among jurists, suggesting that Roman law should be interpreted in the context of the time in which it was created. The glossators and commentators’ belief in the universality and legal validity of the Roman law gone into the past. The new method (mos gallicus) was gradually transformed from a history- and philology-driven study of the Roman law texts into a general historicist point of view, which turned the main interest of jurists to domestic law and customs. Thus, the humanist approach became the basis from which the idea of the uniqueness of the domestic legal order was born. This idea was transferred to the field of public law and led to the belief that the principles of the domestic legal order should be derived not from universal categories of the alien Roman law, but from real political practices of the past, local customs and “ancient constitutions”. Nevertheless, the historical method itself, due to its focus on unique, specific features of legal orders, could not ensure the establishing of a new public law science. In this regard, Jean Bodin developed and later applied a peculiar comparative-legal approach, which, as the French jurist believed, should have served to create a system of universal concepts of public law theory.