The Theatre of Balbus (Theatrum Balbi), which stood in the Campus Martius, was built by Lucius Cornelius Balbus and dedicated in 13 BCE. It was the third, and smallest, stone theatre to be built in Rome, with seating for some 8,000 spectators.
Nothing of the Theatre of Balbus survives above ground, but what does remain is located under the Palazzo Mattei Paganica and the area behind the church of Santa Caterina dei Funari.