The steep plateau of Saint-Blaise oppidum is accessible only from the south, therefore easy to defend, was inhabited from the Neolithic until the end of the 14th century with a long interruption during the High Roman Empire (from the 1st to the beginning of the 4th century AD). The excavations undertaken by Henri Rolland in 1935 and continued after his death, have brought to light eight archaeological layers.
There are today remains of Hellenistic rampart (2nd century BC), surmounted by the early Christian walls, a Christian necropolis, and foundations of 11th century church. The Chapelle St-Blaise is a 12th century Romanesque building, restored in the 13th century and whose facade was redone in 1608.
Duino Castle was built by the Wallsee family in 1389 on the cliffs overlooking the Gulf of Trieste. It replaced an older castle from the 11th century. Over time, the Wallsee family disappeared and the castle, after having been used as a prison, became the residence of the Luogar and Hofer.
At the end of the 19th century it became the property of Prince Alexander von Thurn und Taxis from the Czech branch of the House of Thurn and Taxis. It remains with the family to this day with his great-grandson Prince Carlo Alessandro della Torre e Tasso, Duke of Castel Duino the current owner. The castle has been opened to the public as a museum and park.