Theater of Marcellus was a Roman theatre, built in the 1st century BCE in the southern part of the Field of Mars in Rome.
The site for this object was already designated by Julius Caesar, his assassination in 44 BCE however, it caused the work to be interrupted. He resumed it by Octavian Augustus, dedicating the building to his prematurely deceased in 23 BCE nephew Marcus Claudius Marcellus. In 17 BCE the theatre was an arena for ceremonies related to ludi saeculares, but the official completion of construction took place only in 13-11 BCE. The theatre was destroyed at the end of antiquity.
It is the only theatre in Rome that has survived to our times, retaining – at least partially – its external appearance. The structure reflects the way the Romans adapted the Greek invention: the outer wall rises over three stories, due to the fact that the theatre was erected on a flat site, not in a depression. The first storey is built in the Doric order, the second in Ionic, and the third in Corinthian. The capacity of the facility is estimated at 10-14 thousand viewers.