Hordes of tourists in Rome queue up every day to stick their hand in the Mouth of Truth while skipping the adjoining church, the fascinating Basilica of Santa Maria in Cosmedin. Located near the Circus Maximus in the site of the Forum Boarium, Rome's ancient cattle market, the church is one of the city's finest examples of mediaeval ecclesiastic architecture and is renowned for its Cosmatesque floors.

The basilica, whose origins date to the sixth century and possibly much earlier, is also known for housing a more unexpected relic: the skull of Saint Valentine. The skull, crowned with a garland of flowers and emblazoned with "San Valentino" across its forehead, can be found in the side altar on the left side of the church.