Isar Fortress (Тврдината Исар, Исарот во Штип) is a special landmark for the city of Stip (Штип) and it is located 150 meters above the river Bregalnitsa (Брегалница).
In 2009 discovered was the tunnel that leads from the river to the top of the fortress, which confirmed the most famous Stip legend, how the city was conqured through a secret tunnel under the fortress, a story also told in 17th century by Turkish traveler Evliya Çelebi.
The city of Stip in located in the center of Macedonia and is famous for its rich and impressive history. Byzantines called it “Στιπειoν” and Ottoman Turks “Istib”.
Astibos is the ancient name of the river Bregalnitsa which passes through the city and trough the history protected the city from enemies and invaders.
Isar is the most remarkable and also most impressive hill whose rocks prevailed over Bregalnica. The highest flattened isohypses stand preserved citadel of the city where more than a millennium had its residence city administration and elite.
The walls that surround this area are very massive and solid, and according to old tradition, in plaster the masons have put thousands of eggs for building's walls. Such is the main tower that was flat while the mayor and most difficult to conquer.
At the foot of the Isar citizens lived and that part of the Middle Ages called Varos. In 1018 the armies of the Byzantine Empire conquered the city in which the reigning king of previous decades was Samuel.
During the XII and XIII century Byzantine city of Stip is the crucial and has based its growth on trade and handicraft. The medieval town until the end of the XIV century extended around the eastern and southern side of the fortress and small creek Otinja.
Around 1300 the town was under the domination of the Serbian kingdom and dynasty Nemanikji (Неманиќи).
Ottoman Turks captured the city after they discovered the secret corridor of the acropolis, leading from Bregalnica.
From that side of the fortress and the city is not accidental Turks formed the district of Stip called Novo Selo.
City prosperity in the Ottoman period is visible in several preserved buildings as Husa Medin Pasha Mosque, also known as St. Elijah and Bezisten representing architectural masterpiece located in the city center.