The medieval Tumbo church is very well-preserved. It was built in a Romanesque style in the 1100s. The sacristy and porch were added in the 15th century. The original tower was collapsed in 1734 and the new one was built couple of years later.
The pulpit was made in 1630. The sandstone-made font date from the 1100s and polyptychs date also from the Middle Ages.
References: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.