Lambros Kamberidis presents here, written in French, his study that he initially considered as a necessary second volume in the treatise of Nikolaos Mavrokordatos On Duties (Bucharest 1719), which he himself published in a bilingual edition (MIET, 2014), in his own translation and interpretive commentary, also in French. An essay on "duties" (officia) on the threshold of the Enlightenment was, for the multilingual author, the ideal companion of the contemporary reader in understanding Mavrokordatos' opus magnum, who wrote his work as a model of constitutional law when he took over the leadership of the Danubian provinces, with the aim of serving as a code of coexistence for a reconstituted society within the framework of the Ottoman regime. The voivode of Moldavia wanted to be the carrier of the Western tradition that legitimized any kind of ruler, high priest, supreme state governor or judge to assume the "dignity" of his duties, and to bring the "person" of the function he exercises as a guarantee for his services in public affairs (res publica). The first moral characteristics of Duties draw from the Platonic virtues, justice, wisdom, courage, and temperance. Today, the researcher of the idea of Duties and the Mavrokordatos adventure, in his work Les devoirs et la chose publique (Duties and public affairs), embarks on a historical, philosophical, theological, political, and legal journey, correlating duties with virtues, traversing the sophiological texts, referring to the sources of advisory literature as well as to popular culture with monastic influences, investigating the interactions in the dual cultural fertile space of southeastern Europe in the 17th and 18th centuries, the so-called "Greek-Romanian education". The French Revolution marked the end of the sovereignty of duties in the state system of the old regimes. From the time of the Stoics until the 18th century, duties were inscribed in the constitutional institutions of the state and determined the extent of citizens' involvement as social entities in their relations with the authorities, as well as in their relations with other individuals, ensuring the harmonious composition of society. After the Revolution, the primary significance of duties in the order of society diminished, in order to emphasize human rights (droits de l'homme) that undermined the concept of duties.