Raetia or Rhaetia (ˈriːʃ(i)ə , ˈrae̯ti.a) was a province of the Roman Empire, named after the Rhaetian people. It bordered on the west with the country of the Helvetii, on the east with Noricum, on the north with Vindelicia, on the south-west with Transalpine Gaul and on the south with Venetia et Histria, a region of Roman Italy.
It thus comprised the districts occupied in modern times by eastern and central Switzerland (containing the Upper Rhine and Lake Constance), southern Germany (Bavaria and most of Baden-Württemberg), Vorarlberg and the greater part of Tyrol in Austria, and part of northern Lombardy in Italy. The region of Vindelicia (today eastern Württemberg and western Bavaria) was annexed to the province at a later date than the others. The northern border of Raetia during the reigns of emperors Augustus and Tiberius was the River Danube. Later the Limes Germanicus marked the northern boundary, stretching for 166 km north of the Danube. Raetia linked to Italy across the Alps over the Reschen Pass, by the Via Claudia Augusta.
The capital of the province was Augusta Vindelicorum, present-day Augsburg in southern Germany.
Switzerland in the Roman era
Little is known of the origin or history of the Raetians, who appear in the records as one of the most powerful and warlike of the Alpine tribes. Livy states distinctly that they were of Etruscan origin (a belief that was favored by Niebuhr and Mommsen). A tradition reported by Justin and Pliny the Elder affirmed that they were a portion of that people who had settled in the plains of the Po and were driven into the mountains by the invading Gauls, when they assumed the name of "Raetians" from an eponymous leader Raetus. Even if their Etruscan origin be accepted, at the time when the land became known to the Romans, Celtic tribes were already in possession of much of it and had amalgamated so completely with the original inhabitants that, generally speaking, the Raetians of later times may be regarded as a Celtic people, although non-Celtic tribes (es.