ENWhy did Eustachy Tyszkiewicz decide to establish a public museum in Vilnius? What were his views on museum activity? What meaning did he see in this activity? The answers to these questions would allow us to deepen our understanding of the phenomenon of the Vilnius Museum of Antiquities and to trace the beginning of the entire process of museum activity in the lands of the Grand Duchy of Lithuania. Unfortunately, there are no diaries or memoirs that could answer these questions more explicitly. Therefore, we will apply the method of historical reconstruction and rely mainly on ancillary facts. We can distinguish three sources of information reflecting the development of Tyszkiewicz’s museological views: firstly, his acquaintance with the museum institutions of that time; secondly, printed publications containing various information on museums; and thirdly, his communication with colleagues - scholars, museum employees and collectors. The intellectual life in Europe in the first half of the 19th century was greatly influenced by Voltaire’s traditions - freethinking, scepticism and the prevalence of the positivist spirit. The Great French Revolution of 1791 gave birth to the idea of a museum of national history. Private collecting of historical heritage also became more active in the former lands of the Grand Duchy of Lithuania in the first half of the 19th century. The activity of private collectors of antiquities created the conditions for the appearance of the first public museum collections. The attention of collectors to the history and culture of their homeland also increased. They were the first to form the basis of source research necessary for archaeological, ethnographic and art critical studies. Museum objects held in private collections, as well as in Tyszkiewicz’s Lahoysk (Minsk governorate, Barysav district), increasingly aroused public interest.Thus, there was a tendency to restructure closed collections into public museums. During the short time of his service in the Chapter of Russian Imperial and Tsarist Orders in Saint Petersburg (1833-1835), Tyszkiewicz had access to the collections of the famous Kunstkammer, the Rumyantsev Museum and the museums of Countess Alexandra Laval (Александра Григорьевна Лаваль, 1772-1850) and Pavel Svinyin (Павел Петрович TyгойСвиньин, 1787-1839). We cannot rule out a possibility that at that time he made an acquaintance of the author of the project of the first national museum in the Russian Empire, Friedrich von Adelung (Rus. Федор Павлович Аделунг, 1768-1843). While serving at the chancellery of the Governor General of Chernigov, Poltava and Kharkov in 1840, Tyszkiewicz had enough time to explore the collection of the Coin Cabinet of Kharkov University, one of the best in the empire, and the Zoology Cabinet of this school. Tyszkiewicz knew from his correspondence with the members of the Odessa Society of History and Antiquities about the activity of archaeological museums in the cities on the northern shore of the Black Sea.His trip to the Scandinavian countries and, in particular, the capital of Denmark Copenhagen was particularly important from the viewpoint of museology. The scholar’s attention was above all attracted by the Nordic Museum of Antiquities (Det Kgl. Museum for Nordiske Oldsager or Oldnordisk Museum), founded by the Danish antiquarian and archaeologist Christian Jiirgensen Thomsen (1788-1865) in 1819 and based on the theory of “three centuries”. Thus, when addressing the Governor General of Vilnius Ilya Bibikov (Илья Гаврилович Бибиков, 1794-1867) with a request to establish a museum in Vilnius in 1848, Tyszkiewicz was already well aware of the public mission of the museum and well acquainted with the experience of Russia and Europe in collecting, systemising and presenting museum collections. [From the publication]