Trieste or Tergeste, which dates to the protohistoric period, was enclosed by walls built in 33–32 BC on Emperor Octavian’s orders. The city developed greatly during the 1st and 2nd centuries.

The Roman theatre lies at the foot of the San Giusto hill, facing the sea. The construction partially exploits the gentle slope of the hill, and much of the theatre is made of stone. The topmost portion of the amphitheatre steps and the stage were supposedly made of wood.

The statues that adorned the theatre, brought back to light in the 1930s, are now preserved at the Town Museum. Three inscriptions from the Trajan period mention a certain Q. Petronius Modestus, someone closely connected to the development of the theatre, which was erected during the second half of the 1st century.

(source: http://en.wikipedia.org/wiki/Trieste#Roman_theatre)