The Curiosum mentions it as if still in use, and gives the number of spectators it would contain as 20,000. In the Middle Ages it was, like all the other great buildings of Rome, turned into a castle by Pietro Leone, a nobleman of great power in the time of Urban II. and Pascal II., and celebrated for his factious violence. The shape of the building was thus completely altered. The great family of the Savelli came into possession of it in the twelfth century, following Pietro Leone, and after them the Orsini. The lower stories are now occupied by workshops, small wine vaults, and rag and bone warehouses, frequented by the rustics of the Campagna, who are usually to be seen in considerable numbers in the Piazza Montanara in front of it. From the piazza two rows of the exterior arcades are visible, each containing twelve arches and thirteen columns of travertine. The lower arcade is now buried to the depth of one third of its surface below the level of the present ground. Its half columns are of the Doric order, with a Doric entablature and triglyphs, and are surmounted by a low attica with projecting bases for the half columns of the upper arcade. The height of this upper arcade was originally somewhat less than that of the lower. It has half columns of the Ionic order, carrying a simple entablature with an architrave of three projecting ledges, a plain frieze, and a cornice with toothed mouldings. No actual remains of a third arcade above these two are now to be found, but it can hardly be doubted that one existed originally, and that it was of the Corinthian order. Some parts of the substructions of the seats are said to be still extant in the cellars of the Savelli residence, consisting of diverging walls similar to those still to be seen in the Coliseum. By means of these, the ground plan of the cavea of the theatre can be completely restored. There are no remains of the scena. Upon one of the fragments of the Capitoline plan, partly restored, the name Theatrum Marcelli is legible. There seems, however, to be some doubt as to the genuineness of this fragment. [Sidenote: The Ponte Rotto.] The bridge near the theatre of Marcellus is now called the Ponte Rotto from its broken condition. The two remaining arches are not ancient, but probably stand upon the site of an ancient bridge which was called the Pons Æmilius. Livy mentions this bridge as the first stone bridge built over the Tiber, and states that it was begun in B.C. 179 by M. Fulvius Nobilior, and M. Æmilius Lepidus the censor, whose name was given to the Basilica Æmilia, and that it was finished in B.C. 142 by the Censors Publius Scipio Africanus, and L. Mummius. The bridge was named after M. Æmilius Lepidus as Pontifex Maximus, and as a more popular statesman than Fulvius. The bridge afterwards bore the name pons lapideus, from being the first stone bridge built over the Tiber, and in contradistinction to the pons sublicius.