The Teatro Romano in Trieste was built in the first century BC and expanded in the second century AD. It had seats for from 3,500 to 6,000 visitors. It was probably built by the Trieste Quinto Petronio Modesto , prosecutor Emperor Trajan.
Over the centuries, the theater was left under the houses that were built above. Considered lost, it was identified in 1814 and unearthed in 1938 during the demolition of this part of the old city. The statues and inscriptions found in the excavations are kept in the San Guisto Castle.
Nowadays Teatro Romano is still occasionally used for outdoor summer shows.
FYI this is not an amphitheater because it is not in the round. It is simply a theater.
The Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.