San Colombano Castle originates probably from the 6th century AD, but if was mentioned first time in the 10th century. The current castle was built by Frederick I, Holy Roman Emperor (Federico Barbarossa). During his second visit to Italy, he destroyed the existing castle, but decided to build a new one in 1164. The next reconstruction began in 1370. Later it has been conquered and rebuilt several times.
Herceg Novi was founded (on a former small fishing village, existing since Roman Empire times) as a fortress in 1382 by first Bosnian King Stjepan Tvrtko I and was called Sveti Stefan or Castelnuovo. The Turks conquered Herceg Novi in 1482, and ruled for 200 years, until 1687. However, there was a short pause between 1538 and 1539 when it was held by the Spaniards before they were defeated in the Siege of Castelnuovo. Turkey ruled again until 1687, from then until 1797, the town was ruled by the Venetian Republic.
The Herceg Novi old town is amazing. It is on a fairly steep hill that leads all the way down to the sea. Wandering through the small stairways to the various plazas and fortresses is a many hour adventure.