Middle Ages
The toponym Trebinje is first attested in De Administrando Imperio by Constantine VII (905-959), when describing the geography of the Serbs. Travunia was a province of the Serbian Principality under the Vlastimirović dynasty. The first known office holder was Beloje, a count, who ruled under Prince Vlastimir (also possibly under Radoslav or Prosigoj, fl. 819). In the mid-9th century, Vlastimir married his daughter to Krajina, the son of Beloje, and gave him the Župa of Trebinje to govern under his suzerainty. The Belojević noble family was entitled to rule Travunia; Hvalimir, and his son Čučimir, continued the office under the Serbian crown.
The town commanded the road from Raguša to Constantinople, which was traversed in 1096 by Raymond of Toulouse and his crusaders. Under the name of Tribunia or Travunja (the Trebigne of the Ragusans), it belonged to the Serbian Empire until 1355. Trebinje became a part of the expanded Medieval Bosnian state under Tvrtko I in 1373. There is a medieval tower in Gornje Police whose construction is often attributed to Vuk Branković. The old Tvrdoš Monastery dates back to the 15th century.
In 1482, together with the rest of Herzegovina (see: Herzog Stjepan Vukčić Kosača), the town was captured by the Ottoman Empire. The Old Town-Kastel was built by Turks on the location of the medieval fortress of Ban Vir, on the western bank of the Trebišnjica River. The city walls, the Old Town square, and two mosques were built in the beginning of the 18th century by the Resulbegović family. The 16th-century Arslanagić bridge (or Perovica bridge) was originally built at the village of Arslanagić, 5 kilometres (3.1 mi) north of the town, by Mehmed-Paša Sokolović, and was run by Arslanagić family for centuries. The Arslanagić Bridge is one of the most attractive Ottoman-era bridges in Bosnia and Herzegovina. It has two large and two small semicircular arches
