San Nicolás church was built in the 12th century not only with religious functions, but also as a defensive bastion of the quarter during the strife with the neighbouring ones of St. Saturnino and Navarrería. The military role is evident in the watch tower. In 1222 the original Romanesque church was destroyed by a fire, and was replaced by a new building, consecrated in 1231.
The interior is in Gothic style, from different phases. It houses a Baroque organ. Exteriorly, of the Gothic period only two portal are visible today, as well as the apse. The corner portico was designed by Angel Goicoechea and built by a local contractor Blas Morte in the 1880s.
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.