At first sight, it appears to be smaller version on the Colosseum, which was nevertheless built a good 83 years after the theatre. The differences are more evident on taking a closer look. The Theatre of Marcellus, for example, is semicircular, while the Colosseum is  completely round as indeed an amphitheatre should be.
The Theatre of Marcellus is perhaps the oldest theatre to have survived until the present day. Initially begun by Julius Caesar, it was completed by the Emperor Augustus in 11 B.C., and was dedicated to his nephew Marcus Claudius Marcellus, who died five years before it was finished at the age of just 19.
It very much comes alive in the summer, where it provides a sumptuous setting for the “Tempietto Concerts” , where top artists from Academies, High Schools of Music and Cultural Institutes entertain an Italian and international public.