Siscia is described by Roman writers as a great town in the south of Upper Pannonia, on the southern bank of the Savus, on an island formed by that river and two others, the Colapis and Odra, a canal dug by Tiberius completing the island. It was situated on the great road from Aemona to Sirmium. According to Pliny the name Segestica belonged only to the island, and the town was called Siscia; while Strabo says that Siscia was a fort in the neighbourhood of Segestica;[8] but if this was so, it must be supposed that subsequently the fort and town became united as one place. Siscia was from the first a strongly fortified town; and after its capture by Tiberius, in the reign of Augustus, it became one of the most important places of Pannonia; for being situated on two navigable rivers, it not only carried on considerable commerce, but became the central point from which Augustus and Tiberius carried on their undertakings against the Pannonians and Illyrians. Tiberius did much to enlarge and embellish the town, which as early as that time seems to have been made a colonia, for Pliny mentions it as such: in the time of Septimius Severus it received fresh colonists, whence in inscriptions it is called Col. Septimia Siscia. The town contained an imperial mint, which produced coins under a series of emperors between 262 and 383 AD.