Until the 16th century, Danish was a continuum of dialects spoken from Schleswig to Scania with no standard variety or spelling conventions. With the Protestant Reformation and the introduction of printing, a standard language was developed which was based on the educated Copenhagen dialect. It spread through use in the education system and administration, though German and Latin continued to be the most important written languages well into the 17th century. Following the loss of territory to Germany and Sweden, a nationalist movement adopted the language as a token of Danish identity, and the language experienced a strong surge in use and popularity, with major works of literature produced in the 18th and 19th centuries. Today, traditional Danish dialects have all but disappeared, though regional variants of the standard language exist. The main differences in language are between generations, with youth language being particularly innovative.