As they accumulated crowns and titles, the Habsburgs developed a unique family tradition of multilingualism that evolved over the centuries. The Holy Roman Empire had been multilingual from the start, even though most of its emperors were native German-speakers. The language issue within the Empire became gradually more salient as the non-religious use of Latin declined and that of national languages gained prominence during the High Middle Ages. Emperor Charles IV of Luxembourg was known to be fluent in Czech, French, German, Italian and Latin. The last section of his Golden Bull of 1356 specifies that the Empire's secular prince-electors "should be instructed in the varieties of the different dialects and languages" and that "since they are expected in all likelihood to have naturally acquired the German language, and to have been taught it from their infancy, shall be instructed in the grammar of the Italian and Slavic tongues, beginning with the seventh year of their age so that, before the fourteenth year of their age, they may be learned in the same". In the early 15th century, Strasbourg-based chronicler Jakob Twinger von Königshofen asserted that Charlemagne had mastered six languages, even though he had a preference for German.