Trebinje first mentioned in X century by Constantine Porphyrogenitus called Tribunija . At that time, Trebinje was on the caravan route that led from Kotor and Dubrovnik to Bosnia, Serbia and Montenegro. The first urban city takes on the contours of the Middle Ages . At the beginning of a new era and the Middle Ages Trebinje Region is being developed under the strong influence of the Byzantine Empire , but in the fifteenth century , long after national independence , fell under the centuries-long Ottoman administration , and until 1918 the Austro-Hungarian Empire. Trebinje's old town was founded in the early seventeenth century on the banks of the river Trebišnjica and was named Ban Vir . Today, the old town - Kastel, formed by former trade and craft center. The period of Austro-Hungarian rule and today are reminiscent of the building of a public nature , administrative buildings , barracks , schools and more. This style is fitted in the Mediterranean center of Trebinje. The turbulent history in the region has left its traces and monuments of cultural and historical heritage : medieval necropolis , where they discovered two inscriptions in Cyrillic from the twelfth century , the monastery Tvrdoš (IV - VI century) , Monastery Longer (XVI century) , Petro - Paul's Monastery ( IV- VI century) , monastery Zavala (XIII century) .