Sofia, Bulg. Sofiya, city (1993 pop. 1,114,476), capital of Bulgaria, W central Bulgaria, on a high plain surrounded by the Balkan Mts. It is Bulgaria's chief industrial, transportation, and commercial center. Among the chief manufactures are engineering and metal products, foodstuffs, textiles, rubber and leather goods, furniture, footwear, and chemicals.

A Thracian settlement once occupied the site of Sofia. It was taken by the Romans in A.D. 29 and flourished, especially, under the Emperor Trajan, as Sardica. Destroyed by the Huns in 447, the city was rebuilt (6th cent.) by Byzantine emperor Justinian I and renamed Triaditsa by the Byzantines. It formed part of the first Bulgarian kingdom (809-1018), reverted to the Byzantines (1018-1186), and was included in the second Bulgarian kingdom (1186-1382). Known as Sredets under the Bulgars, it was renamed Sofia or Sophya in 1376. Sofia passed to the Ottomans in 1382 and became the residence of the Turkish governors of Rumelia. Taken by the Russians in the Russo-Turkish War of 1877-78, it became (1879) the capital of newly independent Bulgaria. During World War II the Russians captured Sofia from the Germans (1944).

The city has a university (founded 1889) and numerous other educational and cultural facilities. It is the see of an Eastern Orthodox metropolitan and of a Roman Catholic bishop and also retains many old churches, mosques, and synagogues. Landmarks include the parliament building, the state opera house, the former royal palace, the Church of St. George (4th-5th cent.), the Church of St. Sofia (6th-7th cent.), the Banya Bashi mosque (1474), and the Alexander Nevski Cathedral.

SOFIA: see infrared astronomy.

ancient Serdica

City (pop., 2001: 1,096,389), capital of Bulgaria. Established as a Thracian settlement circa 8th century BC, it flourished under the Romans. Plundered by the Huns in the 5th century AD, it was rebuilt under the Byzantine Empire. In 809 it became a Bulgarian town but reverted to Byzantine rule from 1018 to 1185, when the second Bulgarian empire was established. The Turks held it from 1382 until it was liberated by the Russians in 1878. In 1879 it was made the Bulgarian capital. It is the country's principal transportation and cultural centre and the site of many industries. Among its educational institutions is the University of Sofia (1888), Bulgaria's oldest university. Its historical monuments include the 6th-century church of St. Sofia.

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