(the ancient Arretium, Arretinus, or Aretinus), a city of Tuscany, capital of a province of the same name, situated on the Chiana, an affluent of the Arno, 40 miles south-east of Florence. Lat. 43. 18. 6. N. Long. 11. 53. 35. E. It is the seat of a bishop and of a court of appeal; and has a magnificent cathedral of the thirteenth century with some fine monuments, many churches and cloisters, several educational institutions, a surgical school, hospital, library, and museum. In the principal square stands a magnificent building called Le Loggie, containing the custom-house, the theatre, town-hall, &c., with a portico 400 feet in length. Its principal manufactures are woollen stuffs and pins. Pop. 9500. Arezzo is the birthplace of many eminent persons, among whom were Maecenas, Petrarch, Vasari, Bracci, Leonard Bruin, called Aretin, Guido the great improver of musical notation, and the naturalist Redi.

Arretium was one of the most ancient and powerful of the Etruscan cities. History is silent as to the period when it became subject to the Roman sway; but after the conquest of Italy, Arretium was a military post of the highest importance to the Romans, as commanding the western entrance into Etruria, and the valley of the Tiber from Cisalpine Gaul; and here Flamininus was posted with his army to oppose the advance of Hannibal in the second Punic war. On the commencement of the civil war in B.C. 49, this was one of the first places that Caesar occupied after crossing the Rubicon. The only ancient remains in Arezzo are some small portions of a Roman amphitheatre; and hence some suppose that the modern city occupies the site of the Roman Arretium, but that the ancient Etruscan city of that name was distant two or three miles to the south-east, where some remains of what are called cyclopean walls are still visible. Many valuable relics of antiquity have been found at Arezzo, among which are numerous works in bronze, especially the Chimera and the statue of Minerva, which are now preserved in the gallery at Florence.

Pliny informs us that its pottery was celebrated; and many specimens have been found there of a peculiar red ware figured in relief, wholly different from the painted vases of southern Etruria and Campania.