The article explores the sources of the Lithuanian sociology in the Russian Empire in the first decade of the 20th century. It surveys the history of the emergence of sociology discipline in St. Petersburg's Roman Catholic Spiritual Academy, where a number of Lithuanian studied, and the focus is on the academic activities and social thought of J. Matulaitis in 1907-1909. J. Matulaitis is known as the renovator or the founder of monasteries and as Bishop of Vilnius. In 1987, he was beatified by Pope John Paul II. This study aims to analyze, on the basis of the chronicle of Academy, articles on social issues in the magazine "Draugija" in 1909, memories of students and letters of G. Matulaitis, his contribution to the science of sociology. The author of the article claims that the department of Sociology at the Academy of St. Petersburg was the first in the Russian Empire. It was founded by the initiative of Lithuanian students and professors, and its establishment in 1907 predated the department of sociology of the Private Institute of Psycho neurology dated to 1911 (first mentioned in historical researches of Russian scientists). The first professor of Sociology in the Academy was a Lithuanian, i. e. J. Matulaitis. His lectures on sociology made a significant impact on the development of social sciences in Lithuania. The professors of the Academy J. Matulaitis, P. Bucys, Maironis, and others organized the Lithuanian social courses to the public in Kaunas in 1909, and such sociologists as S. Sulte, K. Saulys, K. Paltarokas, who delivered lectures, became well-known specialists in this sphere. In spite of J. Matulaitis' obvious contribution to the evolution of Lithuanian sociology, he was not a sociologist. His insights and interdisciplinary knowledge helped him to create a new science, the so-called Christian Social Teaching. The thought and the attitudes of J. Matulaitis got ahead of the Pope's thought even a few decades and are relevant to the present day. [ABSTRACT FROM AUTHOR]