The term Latinitas in this article includes the studies of Latin language in Grand Duchy of Lithuania, imitation of classical Latin authors, the historical, religious, polemical and fiction Latin Literature created on the basis of this imitation. The Latin language was used in Lithuania from 13th century and the letters and documents of Grand Dukes of Lithuania Mindaugas (Mendoge), Gediminas (Gedeminne), Vytautas (Witold) were written in Latin. There are many common reasons which defined the usage of the Latin language in the West and Middle Europe where Latinitas was apprehensible as equivalent of humanitas, however in the Lithuania in 16th-17th centuries the Latin language played much more important role than in other countries in Europe. In Lithuania it was not only the subject of education, the sign of development, the means of intelectual creation but also important argument which emphasised the political independence of Lithuania and the national identity of Lithuanians. The College of Jesuits founded in Vilnius in 1570 and the Vilnius University (Universitas et Academia Vilnensis Societatis Iesu) which was acting from 1579 till 1773 strongly influenced the strengthening of the Latin language in the Grand Duchy of Lithuania. The universal curriculum of studies, typical manuales, higher level of teaching allowed the professors and students of Vilnius University equally take part in scientific and intellectual activities of West Europe.