The study offers a documented reconstruction of the political, diplomatic and cultural relations between the Kingdom of Naples and the Russian Empire from the beginning of relations in 1777 until 1820. The search for testimonies linking Italy and Russia was based primarily on unpublished manuscript materials of the Naples State Archive from the funds of the Ministry of Foreign Affairs and Maresca di Serracapriola. These documents are mainly diplomatic correspondence between Neapolitan ministers in St. Petersburg and the Ministry of Foreign Affairs of the Bourbon dynasty, starting from 1763. The article analyses a considerable number of interesting letters, dispatches, memorials, treaties about the role played at the Tsar’s Court by the two first plenipotentiary ambassadors, representatives of Neapolitan King Ferdinand IV. The first was Muzio da Gaeta, Duke of San Nicola, who lived in St. Petersburg from 1779 to 1783 and showed himself more as a literary man and translator than as a politician and diplomat. The other representative of the Bourbon Court was Antonio Maresca, Duke of Serracapriola, who was a longtime minister plenipotentiary assigned to the Russian Court in St. Petersburg from 1787 to 1822. He is remembered for his diplomatic talent and communication skills. During his forty years employment at court, he established close relations with the most powerful Russian politicians and noblesse. After his marriage in 1788 to Anna Wyazemskaya, Serracapriola’s diplomatic career progressed rapidly. So did the alliance between the Neapolitan and Russian states, which signed a number of treaties: Trade Treaty in 1787, Treaty of Alliance in 1798. In 1800, through Duke’s mediation, Paul 1 supported the idea of uniting Catholic and Orthodox churches. Between 1811 and 1812, Tsar Alexander 1 entrusted him with the mission to conclude an agreement with Turkey, Persia and England on behalf of Russia. Duke of Serracapriola died in 1822, remembered as the ambassador of two countries – the Kingdom of Naples and the Russian Empire.