Arabic Ḥalab (حلب), Turkish Halep principal city of northern Syria. It is situated in the northwestern part of the country, about 30 miles (50 km) south of the Turkish border. Aleppo is located at the crossroads of great commercial routes and lies some 60 miles (100 km) from both the Mediterranean Sea (west) and the Euphrates River (east). The city's Arabic name, Ḥalab, is of ancient Semitic origin and is first mentioned in texts at the end of the 3rd millennium BC. In the 18th century BC Ḥalab was the capital of the Amorite kingdom of Yamkhad, and it subsequently came under Hittite, Egyptian, Mitannian, and again Hittite rule during the 17th to 14th centuries. In succeeding centuries it achieved some independence as a Hittite principality. It was conquered by the Assyrians in the 8th century BC, was controlled by the Achaemenian Persians from the 6th to the 4th century BC, and then fell into the hands of the Seleucids, who rebuilt it and renamed it Beroea. It became a first-ranking city of the Hellenistic period and a great commercial entrepôt between the Mediterranean region and the lands farther east. The city was absorbed into the Roman province of Syria in the 1st century BC. It prospered under Byzantine rule but was pillaged and burned by the Persian Sāsānian king Khosrow I in AD 540. In 637 the city was conquered by the Arabs, under whom it reverted to its old name, Ḥalab. In the 10th century the Ḥamdānid dynasty established itself in Aleppo as an independent principality, and the city had a brilliant cultural life under their rule. In the 12th century Aleppo became a centre of Muslim resistance to the Crusaders, who besieged it unsuccessfully in 1124–25. In 1260 Aleppo was taken by the Mongols, who massacred its inhabitants. After an interval of several centuries under the Mamlūks, the city was incorporated in 1516 into the Ottoman Empire, under which it underwent a remarkable commercial revival, becoming the principal market in the Levant. Its prosperity continued until the end of the 18th century, and full economic recovery came in 1880 with the arrival of the railroad. In the 20th century the city became an industrial centre rivaling Damascus. From the Enc. Britt. Also see the Aleppo citadel gallery or the Aleppo Great Mosque.