The culture of the national language, after the disastrous backwardness of the Saxon period, became the basic programme of Stanislawski writers, progressive statesmen and politicians, as well as grammarians or dictionaries. The purpose of this article is to introduce the defenders and promoters of a pure, correct, literary Polish language, beautiful and adapted to the new social and scientific needs. First of all, two Piarists should be mentioned: Stanisław Konarski (1700 - 1773) and Onufry Kopczyński (1735 - 1817). They were followed by other members of the Piarist Order, authors of various linguistic works: Filip Nereusz Golański (1753- 1824), Tadeusz Nowaczyński (1717- 1794), Kazimierz Narbutt (1733-1807), Wincenty Skrzetuski (1745-1791), Franciszek Ksawery Dmochowski (1762-1808) and Franciszek Siarczyński (1758-1829).