The castle was constructed over several centuries, beginning in the 15th century, with significant additions made up until the 17th century. It was built on the site of earlier Roman fortifications.

The Arco di Riccardo dates back to the Roman period, around the 1st century BCE. It is one of the oldest surviving structures in Trieste.

Built in the 1st century AD, during the reign of Emperor Augustus, the Roman Theatre could accommodate between 3,500 and 6,000 spectators.

The square has been a central part of Trieste's urban fabric since the 19th century. Its name, which translates to "Square of the Unification of Italy," commemorates Trieste's incorporation into the Kingdom of Italy in 1918.

The theatre opened in 1801, making it one of the oldest opera houses in Italy. It was originally named the Teatro Nuovo and later renamed in honor of the famous Italian composer Giuseppe Verdi in 1901.

The square has been a central hub for economic and social activity since the 19th century. It is named after the historical Borsa Vecchia (Old Stock Exchange) building.

The church was built between 1861 and 1869 to serve the Serbian Orthodox community in Trieste. This community played a significant role in the commercial and cultural life of the city, particularly during the 18th and 19th centuries when Trieste was a major port under the Austro-Hungarian Empire.

The Canal Grande was constructed between 1754 and 1756, during the period when Trieste was a free port under the Habsburg Empire.