SISSEK (Hungarian, Sziszek; Croatian, Sisak)  , a town of Croatia-Slavonia, in the county of Agram; situated at the confluence of the Save and Kulpa, 3o in. by rail S.E. by S. of Agram . Pop . (1900) 7047 . Sissek has a considerable trade in grain and timber . Its only noteworthy building is an ancient castle, constructed of brick . As the vestiges of its Roman walls tend to prove, Sissek was a large and flourishing city under Roman rule . Augustus made it a military station; Tiberius chose it as his headquarters against the Pannonian rebels; and from Septimius Severus, who made it the centre of a military government, it gained the name of Septimia Sissia . A Segesta, on the Save, is mentioned by Appian, and Strabo distinguishes between this town and the neighbouring Siscia . It seems likely, as St Aymour suggests, that two towns, the native Segesta and the Roman fortress called by Strabo i) Dhriaa 4po6piov, ultimately united under the single name of Siscia . In the 3rd century, under Gallienus and Probus, the city contained the chief imperial mint and treasury; and an engraved coffer, found in Croatia, dating from the 4th century, and representing the five foremost cities of the Empire, includes Siscia along with Rome, Byzantium, Carthage and Nicomedia . Its bishopric was removed to Salona, in 441, when Attila appeared, and thenceforward the city declined . For a brief period, in the 7th and 8th centuries, the conquering Slays made it one of their Zupanates, or governments; but in the loth century it was sacked by the Magyars, and in 1092 its territories were bestowed upon the cathedral chapter of Agram by Ladislaus I., king of Hungary .

Under the walls of its castle, built by this chapter in 1544, the

Turks were thrice defeated in 1593 . At a fourth venture the city fell, only to be evacuated in 1594 . It witnessed a final Turkish defeat in 1641 . See C. de St Aymour, Les Pays sad-slaves de l'Autriche-Hongrie (1883), ch. ii .