AOSTA (anc. Augusta Praetoria Salassorum), town and epis copal see, Piedmont, Italy, province of Aosta, 8om. N.N.W. by rail from the town of Turin, and 48m. direct ; 1,91 of t. above sea level, at the confluence of the Buthier and Dora Baltea, and at the junction of the Great and Little St. Bernard routes. Pop. 5,588 (town) ; 20,731 (commune) . The cathedral, recon structed in the nth century, was much altered in the 15th and 17th; it has a rich treasury including an ivory diptych of 406 with a representation of Honorius. The church of St. Orso, founded 425 and rebuilt in the 12th century, has good cloisters (1133), and there is a picturesque 15th-century priory.
The valley of Aosta fell to the Burgundian kings ; and, after many changes, came under Count Humbert I. of Savoy (Bian camano) in 1032. The privilege of holding the assembly of the states-general was granted in 1189. An executive council was nominated from it in 1536, and continued until 1802. After res toration of the rule of Savoy this was reconstituted by Charles Albert, king of Sardinia, at the birth of his grandson Prince Amedeo, who was created duke of Aosta. Aosta was the birth place of Anselm. For ancient remains see AUGUSTA PRAETORIA SALASSORUM.
See P. Toesca, Aosta (1911) .