Proceeding in a direct line from the Arch of Janus, we reach the _Church of Sta. Maria in Cosmedin_, on the site of a Temple of Ceres, dedicated by the consul Spurius Cassius, B.C. 493, and afterwards re-dedicated to Ceres and Proserpine, probably by Augustus, who had been initiated into the Eleusinian mysteries in Greece. The church was built in the basilica form, in 782, by Adrian I., when the name Cosmedin, from the Greek κοσμος, is supposed to have been given, from the ornaments with which he adorned it It was intended for the use of the Greek exiles expelled from the East by the iconoclasts under Constantine Copronimus, and derived the epithet of Sta. Maria in Scuola Greca, from a "Schola" attached to it for their benefit. Another relic of the Greek colony which existed here is to be found in the name of the adjoining street, Via della Greca. In the middle ages the whole bank of the river near this was called Ripa Greca. The interior of this church is of great interest. The nave is divided from the aisles by twelve ancient marble columns, of which two have especially curious antique capitals, and are evidently remains of the temple which once existed here. The choir is raised, as at S. Clemente. The pavement is of splendid Opus Alexandrinum (1120); the ambones are perfect; there is a curious crypt; the altar covers an ancient bason of red granite, and is shaded by a gothic canopy, supported by four Egyptian granite pillars; behind it is a fine episcopal throne, with lions, said to have been used by St. Augustine, an ancient Greek picture of the Virgin, and a graceful tabernacle of marble inlaid with mosaic, by _Deodato Cosmati_. In the sacristy is a very curious mosaic, one of the few relics preserved from the old St Peter's, A.D. 705. (There is another in S. Marco at Florence.) Crescimbeni, the founder and historian of the Arcadian Academy (d. 1728), is buried in this church, of which he was a canon. On St. Valentine's Day the skull of St. Valentine, crowned with roses, is exhibited here. In the portico is the strange and huge mask of stone, which gives the name of _Bocca della Verita_ to the neighbouring piazza. It was believed that if a witness, whose truthfulness was doubtful, were desired to place his hand in the mouth of this mask, he would be unable to withdraw it, if he were guilty of perjury. "Cette Bouche-de-Vérité est une curieuse relique du moyen âge. Elle servait aux jugements de Dieu. Figurez-vous une meule de moulin qui ressemble, non pas à un visage humain, mais au visage de la lune: on y distingue des yeux, un nez et une bouche ouverte où l'accusé mettait la main pour prêter serment. Cette bouche mordait les menteurs; au moins la tradition l'assure. J'y ai introduit ma dextre en disant que le Ghetto était un lieu de délices, et je n'ai pas été mordu."--_About, Rome Contemporaine._ On the other side of the portico is the tomb of Cardinal Alfanus, ob. 1150.