SISSEK (Hungarian, Sziszek; Croatian, Sisak), a town of Croatia-Slavonia, in the county of Agram; situated at the confluence of the Save and Kulpa, 30 m. 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 Segesla, 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) 2t(ma Qpovpiov, 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 Slavs made it one of their Zupanates, or governments; but in the 10th 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 sud-slaves de I' Autriche-Hongrie (1883), ch. ii.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)