Sibiu was initially a Roman city (Cibinium), whose name was derived from that of the river, a tributary of the Olt, which rises in the Cibin Mountains southwest of the city. Sibiu was refounded by Saxon (German) colonists in the 12th century as Hermannsdorf (later Hermannstadt). The old medieval town is in two parts, the upper town built on a terrace and the lower town on the banks of the Cibin, the two being connected through an old district by narrow, cobbled alleys called the Fingerling Stairway.

A citadel, built by the Saxon settlers in the 13th century, was destroyed by the Tatars in 1241 and rebuilt in the 14th century. Massive brick walls erected around the upper town gave it the nickname “Red Town,” for the colour of the walls, which repelled several Turkish attacks in 1432, 1438, and 1442. During that time, Sibiu was an important craft and cultural centre of the German communities in Transylvania, boasting 19 guilds in 1376. In 1541 Transylvania became an autonomous Turkish vassal state; but, as the Turks later withdrew from Hungary, Austria regained Transylvania after brief Romanian opposition in 1699. Sibiu then became the military centre of Transylvania and, on two occasions (1703–91 and 1849–65), the capital. With the rest of Transylvania, it was ceded to Romania in 1918.

Parts of the old fortifications remain, and many of the medieval houses within the walls are historical monuments. The Brukenthal Museum was founded by Samuel Brukenthal, governor of Transylvania (1777–87), in his own Austrian Baroque residence with his collection of paintings, antiques, engravings, and books; it also houses important collections in ethnography, folk art, and natural science. Of the 40 watchtowers on the original inner city wall, three remain—the octagonal tower of the carpenters, the square tower of the potters, and the pentagonal tower of the cloth makers. Also in Sibiu are a massive Lutheran cathedral (built over the 14th and 15th centuries), an Orthodox cathedral (built 1906, modeled on Hagia Sofia in Istanbul), and an 18th-century Roman Catholic church.

Sibiu has a large industrial base; goods produced in the city include machine tools, textile machinery, foodstuffs, leatherware, textiles, and clothing. The city is also a transportation hub, connected by road and railway to Cluj-Napoca to the northwest, to Braşov to the east, and to Bucharest to the southeast. Pop. (2002) 155,045.

judeţ (county), central Romania. The Transylvanian Alps (Southern Carpathians), including the Sebeş, Lotru, and Făgăraş ranges, rise in the southern portion of the county. Settlement areas are in intermontane valleys. Sibiu city, a cultural and industrial centre, is the county capital. Metal products, chemicals, and machinery are manufactured in Sibiu, Mediaş, Avrig, Copşa Mică, and Ocna Sibiului. Building materials, timber, textiles, and leather goods are also produced in the county. A hydroelectric station operates at Sadu. Agricultural activities consist of livestock raising and cereal, orchard, and vineyard cultivation. The towns of Cisnădie and Cisnădiora have historic churches. Răşinari commune is a centre for folk-art production and has an ethnographic museum. Păltiniş and Ocna Sibiului are resorts. Highway and railway connections extend in several directions through Sibiu and Mediaş cities. An airport is near Sibiu. Area 2,097 square miles (5,432 square km). Pop. (2007 est.) 423,156.