to the Frankish Empire, which continued to have local rulers administering the so-called Duchy of Chur. However, after the death of the last Victorid ruler, Bishop Tello, around 765 AD, Charlemagne assigned a Germanic duke to administer the region. Additionally, the Diocese of Chur was transferred by the (pre-Schism) Roman Catholic Church from the Archdiocese of Milan to the Diocese of Mainz in 843 AD. The combined effect was a cultural reorientation towards the German-speaking north, especially as the ruling élite now comprised almost entirely speakers of German. At the time, Romansh was spoken over a much wider area, 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 Romansh-speaking, as were parts of Tyrol. The northern areas, 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 Wallensee were entirely German-speaking. This language shift was a long, drawn-out process, with larger, central towns adopting German first, while the more peripheral areas around them remained Romansh-speaking longer. The shift to German was caused in particular by the influence of the local German-speaking élites and by German-speaking immigrants from the north, with the lower and rural classes retaining Romansh longer. In addition, beginning around 1270, the German-speaking Walser began settling in sparsely populated or uninhabited areas within the Romansh-speaking heartland. The Walser sometimes expanded into Romansh-speaking areas from their original settlements, which then often became German-speaking, such as Davos, Schanfigg, the Prättigau, Schams, and Valendas, which became German-speaking by the 14th century. In rare cases, these Walser settlements were eventually assimilated by their Romansh-speaking neighbors; for instance, Oberhalbstein, Medel, and Tujetsch in the Surselva region. The Germanization of Chur had particular long-term consequences. Even though the city had long before ceased to be a cultural center of Romansh, the spoken language of the capital of the Diocese of Chur continued to be Romansh until the 15th century. After a fire in 1465 which virtually destroyed the city, many German-speaking artisans who had been called in to help repair the damage settled there, causing German to become the majority language. In a chronicle written in 1571–72, Durich Chiampell mentions that Romansh was still spoken in Chur roughly a hundred years before, but