Every year on September 15, the Republic of Belarus celebrates Library Day The holiday was established by presidential decree in 2001 and dedicated to the founding day of the National Library, which is the main book depository of the country The purpose of the holiday is to maintain citizens' interest in reading, as well as to improve the status of library workers Library workers share their professional holiday with readers In recent years, festive events dedicated to Library Day have continued not just for one day, but for a week, because the holiday covers not only libraries, but the entire city Thus, retro exhibitions are held in local history museums, and thematic photo exhibitions are held in galleries; mobile bookcrossing points can be found throughout the city; readers are invited to familiarize themselves with the latest fiction and scientific literature The “Night in the Library” event is of particular interest to citizens Traditionally, these days Belarus hosts foreign delegations to hold joint scientific conferences, round tables, and seminars at which issues are raised about the development of librarianship, the preservation of the country’s national fund and the exchange of cultural heritage The very history of the emergence of libraries in the Western lands of Rus' began in the middle of the 11th century It is believed that the first library on the territory of modern Belarus was the book depository of the Polotsk St Sophia Cathedral At the same cathedral there was a school that trained nuns for the correspondence and translation of books, as well as the correct handling of them Monastic and church libraries played an important role in the formation of the Belarusian language, the national people, as well as the development of spiritual, moral upbringing and education It was the monasteries that were the center for the spread of literacy among the population Information about many small church libraries, if preserved, is scanty and scattered among numerous archives of neighboring states That is why the study and preservation of the history of the development of libraries and their role in the life of the population is one of the most important tasks of modern Belarusian library science