, city (1991 pop. 175,391), SE Serbia and Montenegro, in Serbia, on the Nišava River. An important railway and industrial center, it has industries that manufacture textiles, electronics, spirits, and locomotives. The Roman Naissus, it was the site of a victory ( 269) of Claudius II over the Ostrogoths and was the birthplace of Constantine I (Constantine the Great). In 441 it was destroyed by the Huns but was rebuilt (6th cent.) by Emperor Justinian I. In the Middle Ages the city passed back and forth between the Bulgarian and Serbian empires. The Turks captured it c.1386, were defeated there in 1443 by John Hunyadi, and recaptured it again in 1456. It became (until 1878) their most important military stronghold in the Balkans. It passed to Serbia in 1878. The city retains a medieval fortress that dominates the S Morava valley. The Tower of Skulls (Serbian Cele Kula) was built to commemorate the Serbs massacred by the Turks in the uprising of 1809.