Raetia (so always in inscriptions; classical manuscripts usually use the form Rhaetia), in. ancient geography, a province of the Roman Empire, bounded on the west by the country of the Helvetii, on the east by Noricum, on the north by Vindelicia and on the south by Cisalpine Gaul. It thus comprised the districts occupied in modern times by Graubünden, the greater part of Tirol, and part of Lombardy.
The land was very mountainous, and the inhabitants, when not engaged in predatory expeditions, chiefly supported themselves by cattle-breeding and cutting timber, little attention being paid to agriculture. Some of the valleys, however, were rich and fertile, and produced corn and wine, the latter considered equal to any in Italia. Augustus Caesar preferred Raetian wine to any other.
Considerable trade in pitch, honey, wax and cheese occurred.
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 (v. 33) that they were of Etruscan origin (a view favoured by Niebuhr and Mommsen). A tradition reported by Justin (xx. 5) and Pliny the Elder (Naturalis Historia, iii. 24, 133) 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 their leader Raetus; a more probable derivation, however, is from Celtic rait (mountain land). 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 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 (Lepontii, Euganei) were settled among them.
The Raetians are first mentioned (but only incidentally) by Polybius (xxxiv. 10, iS), and little is heard of them till after the end of the Republic. There is little doubt, however, that they retained their independence until their subjugation in 15 B.C. by Tiberius and Drusus (compare Horace, Odes, iv. 4 and 14).
At first Raetia formed a distinct province, but towards the end of the 1st century A.D. Vindelicia was added to it; hence Tacitus (Germania, 41) could speak of Augusta Vindelicorum (Augsburg) as "a colony of the province of Raetia". The whole province (including Vindelicia) was at first under a military prefect, then under a procurator; it had no standing army quartered in it but relied on its own native troops and militia for protection
In the reign of Marcus Aurelius Raetia was governed by the commander of the Legio iii. Italica. Under Diocletian it formed part of the diocese of the vicarius Italiae, and was subdivided into Raetia prima and Raetia secunda (each under a praeses), the former corresponding to the old Raetia, the latter to Vindelicia. The boundary between them is not clearly defined, but may be stated generally as a line drawn eastwards from the lacus Brigantinus (Lake Constance) to the Oenus (River Inn).
During the last years of the Western Empire, the land was in a desolate condition, but its occupation by the Ostrogoths in the time of Theodoric the Great, who placed it under a dux, to some extent revived its prosperity.
The chief towns of Raetia (excluding Vindelicia) were Tridentum (Trent) and Curia (Coire or Chur). It was traversed by two great lines of Roman roads -- one leading from Verona and Tridentum across the Brenner Pass (in which the name of the Brenni has survived) to Oenipons (Innsbruck) and thence to Augusta Vindelicorum; the other from Brigantium (Bregenz) on Lake Constance by Chur and Chiavenna to Como and Milan.