Raetia (so always in inscriptions; classical manuscripts usually use the form Rhaetia;  /ˈriːʃə/ or /ˈriːʃiə/) was a province of the Roman Empire, named after the Rhaetian (Raeti or Rhaeti) people. It was bounded on the west by the country of the Helvetii, on the east by Noricum, on the north by Vindelicia, on the west by Cisalpine Gaul and on south by Venetia et Histria. It thus comprised the districts occupied in modern times by eastern and central Switzerland (containing the Upper Rhine and Lake Constance), southern Bavaria and the Upper Swabia, Vorarlberg, the greater part of Tirol, and part of Lombardy. Later Vindelicia, today south eastern Wuerttemberg and south western Bavaria was forming part of Raetia. The northern border of Raetia during the times of Augustus and Tiberius was the River Danube. Later the northern boundary was formed by the Limes Germanicus, stretching for 166 km north of the Danube. Raetia was linked to Italy across the Alps over the Reschen Pass, by the Via Claudia Augusta.