Rhaeto-Romance was spoken over a much wider area during Charlemagne's rule, stretching north into the present-day cantons of Glarus and St. Gallen, to the Walensee in the northwest, and Rüthi and the Alpine Rhine Valley in the northeast. In the east, parts of modern-day Vorarlberg were Romance speaking, as were parts of Austrian Tyrol. The northern areas of what is currently Switzerland, called "Lower Raetia", became German-speaking by the 12th century; and by the 15th century, the Rhine Valley of St. Gallen and the areas around the Walensee were entirely German-speaking.