When was standard Lithuanian developed?

Standard Lithuanian was established at the end of the 19th century and the beginning of the 20th century.

While written Lithuanian began to emerge in the 16th century, the development of a uniform standard language followed a long process. In East Prussia, a uniform written language based on the West High Lithuanian dialect was established by the second half of the 17th century. However, within Lithuania itself, the creation of a standard language—based on the (Southern) West High Lithuanian dialect—did not occur until the turn of the 20th century. This standardization effort drew upon various dialects, a practice that had been pioneered by earlier writers such as Mikalojus Daukša and Konstantinas Sirvydas in the 16th and 17th centuries before being revived in the 19th century.1