After the withdrawal of Byzantine, Sirmium also changed its political status. Within boundaries of Hungary, it was no more a frontier town and consequently was given up to a slow decay, for there were no more favorable conditions for its further development. In common with the ancient and Byzantine denominations and relations its old name also disappeared.
When, in the course of the XII century there was formed a new settlement of craftsmen and merchants, it was given a new name after the old Sirmian church of St. Demetrius. The town preserved considerably longer its character of church center and the orthodox diocese of Srem existed until the end of the third decade of the XIII century.
After the devastation of the region of Srem caused by the Tatar invasion the se of the diocese of Srem was transferred to Sirmium, but not to the monastery of St. Demetrius, but to the church of St. Irenaus, situated on the left bank of the Sava. Much longer than the orthodox diocese, the monastery of St. Demetrius which had become the central edifice of the old town kept up its traditions and gave a new name to the town, i.e. Civitas Sancti Demetrii.
Though the monastery had remained under the jurisdiction of the Catholic archbishop, the Greek and Slav monks held on their own until the first quarter of the XIV century. In addition to St. Demetrius, for the progress of the settlement was particularly important the period of renewal and colonization after the Tatar invasion in 1241 – 1242. Before the middle of the XIV century the town was granted the privileges of a free town. In the urban area there were still preserved ancient edifices which were the property of citizens of Mitrovica. The most favorable period in the development of the town took place after the year 1358 when Dubrovnik (Ragusa) had come under the rule of Hungarian kings. This made possible the creation of the colony of Ragusean merchants at Mitrovica, about which we are informed by numerous documents from archives. In 1396, Mitrovica was for the first time burnt down and ravaged by the Turks who took away a part of its population as slaves. When the storm has blown over, the town had to rise from ashes and ruins but the colony of Ragusean merchants was never restored. For a while, about 1451, the town was in possession of the Serbian despot Djuradj Brankovic. In summer 1521 Mitrovica finally came into Turkish hands and it remained under the Turkish rule for almost two centuries.
Dr Sima M. ĆIRKOVIĆ
The text was taken from the monograph SREMSKA MITROVICA, published in 1969 by the Museum of Srem