The theatre was built by L. Cornelius Balbus the Younger in the year 13 AD, behind the Portico d’Ottavia in the heart of the current Jewish quarter. The theatre of Balbus was the third theatrical building in the Campo Marzio, and is proof of how the Greek culture and the fashion of theatrical performances was already very popular by the second half of the I century before Christ. The ruins of the cavea of the theatre are located under the Mattei Paganica Palace, in the area behind the church of S. Caterina deiFunari and in the cellars of the Mattei di Giove Palace. Another excavation, visible in via Michelangelo Caetani, has allowed locating the ruins of the portico in front of the stage, closed by an exedra of pillars, as also shown in a fragment of Forma Urbis, the ancient marble map of the city. The fragment shows the name of the quadriportico, Crypta Balbi, that must have also included at its center a small temple perhaps dedicated to Vulcan. In the Middle Ages the rooms of the theatre hosted the workshops of craftsmen that produced lime, ropes and glass articles.