Blagaj  Blagaj is a village-town in the south-eastern region of the Mostar basin, in the Herzegovina-Neretva Canton of Bosnia and Herzegovina. It stands at the edge of Bišće plain and is one of the most valuable mixed urban and rural structures in Bosnia and Herzegovina, distinguished from other similar structures in its urban layout. Blagaj was most likely named for its mild weather patterns since "blaga" in Serbo-Croatian means "mild". Blagaj is situated at the spring of the Buna river and a historical tekke ("tekija" or Dervish monastery). The Blagaj Tekija was built around 1520, with elements of Ottoman architecture and Mediterranean style and is considered a national monument. Blagaj Tekke is a monastery built for the Dervish. Vrelo Bune, the source of the Buna river, is a strong karstic spring. The river flows west for approximately and joins the Neretva near the village Buna. The historic site of the Blagaj Fort (also "Stjepan-grad" or "Stipan-grad"), on the hill above Blagaj, was the seat of Grand Duke of Bosnia, Stjepan Vukčić, and the birthplace of Bosnian queen Katarina Kosača-Kotromanić. During the classical antiquity there existed an Illyrian fortress and a Roman "castrum". During the reign of Byzantine Emperor Justinian, several fortified towns were built in the area. Blagaj was mentioned in Constantine Porphyrogenitus’ work De Administrando Imperio as Bona, then part of Zahumlje ("Hum"). In the late 12th century, during the rule of Stefan Nemanja (Grand Principality of Serbia), prefect Jurko raised a church dedicated to saints Cosmas and Damian. In the 14th century, during the reign of Bosnian Ban Stjepan II Kotromanić, Hum became part of the Bosnian state. In the 15th century Sandalj Hranić Kosača and his nephew Stephen Vukčić Kosača ruled the Hum and Blagaj territory until the arrival of the Ottomans in 1466. Blagaj is also known as a residential area of Bosnian rulers and particularly of royal families Hranić and Kosača.