1The emperor Justinian I (482-565) is traditionally considered in the 18th century as a hero, the renovator of the Eastern Roman empire, which he extended and reinforced against barbarian threats, and the principal support of Christianity. But especially is owing to him an enormous labor of compilation and elaboration of Roman law, Code justinien, Digeste, Pandectes, complemented by his own legislative work, the Novelles, known in the West as early as the 12th century, and together they became one of the bases of French law (it served as written law in numerous provinces where custom did not prevail). Thus Montesquieu studied it during his legal studies; the evidence of this is the thick volumes of the Collectio juris, or working notes based on the Latin text and commentators and annotators (Mornac, Domat, etc.), compiled for the most part between 1709 and 1713.
2Yet beginning with Romans (XX) in 1734, he shows an accute distrust towards him, as toward all the supposed heroes of history; the “reconquest” of the eastern part of the Empire, due to Belisarius and Narses, was illusory and ephemeral; the conversions were owing only to violence, the pretended suppression of heresy and “sects” an aberration that could recall the attitude of Louis XIV toward the ‘reformed’ protestants (see also Pensées, no. 1671). The famous Corpus juris civilis is hardly better: “The prince also sold his judgments and his laws” (Romans, XX). L’Esprit des lois reiterates these accusations (VI, 5; see also Pensées, no. 1512); the references to Justinian are so many denunciations of an abuse of power, both civil and religious, which appears as the very essence of despotism. This had already been shown in chapter XX of Romans, where Montesquieu discusses at length the historian Procopius, author of a double and embarrassing work, one to the glory of Justinian (The Persian War, Guerre des Vandales, etc.), the other, called Anecdota or Secret History, which relates his turpitudes, in particular the bad influence of the empress Theodora and her scandalous morals (Spicilège, no. 430). For Montesquieu, the truth lies in the secret history; official history reveals only the enslavement of minds, and thus the despotism that lies in wait for all princes.
Iris Cox and Andrew Lewis, “Montesquieu observateur et étudiant en droit, 1709-1720”, in Montesquieu: les années de formation (1689-1720), C. Volpilhac-Auger dir., Cahiers Montesquieu 5, 1999, p. 55-63.
Catherine Volpilhac-Auger, “Ex Oriente nox? le paradoxe byzantin chez Montesquieu”, Dix-huitième Siècle 35 (2003), https://www.persee.fr/doc/dhs_0070-6760_2003_num_35_1_2561.
— “De la Collectio juris à L’Esprit des lois: Justinien au tribunal de Montesquieu”, Montesquieu, la justice, la liberté: hommage de Bordeaux à Montesquieu, Bordeaux: Académie de Bordeaux, 2007, p. 35-43 (repris dans C. Volpilhac-Auger, Montesquieu: une histoire de temps, Lyon, ENS Éditions, 2017 [https://books.openedition.org/enseditions/7400?lang=fr]).