San Valentino, Basilica di is a ruined 4th century pilgrimage basilica built over the tomb of the famous St Valentine, at the catacombs also named after him on the Viale Maresciallo Pilsudski in the Pariole district.
It is located just inside the woods on the boundary of the Villa Glori, opposite the junction with the Viale dei Paroli. Anciently it was reckoned as being at the second milestone on the Via Flaminia, which is nearby.
The Roman martyrology used to list two saints of this name on February 14th, one martyred on an uncertain date on the Via Flaminia two miles north of Rome, and another on the same road at Terni sixty miles north of the city. The argument has raged for centuries as to whether these were the same person, but the revised Roman martyrology has decided for the former and deleted the latter.
According to the Liber Pontificalis, Pope Julius I (336-356) built a basilica over his tomb, which was not actually in the catacombs but outside the entrance. At first this church had three naves, but it was later rebuilt with one nave and aisles separated by colonnaded arcades. Other later additions were a crypt and apse.
The church was on record as being restored and rebuilt several times up to the early 9th century. In 1060 it was restored again, as the abbey church of a Benedictine monastery founded on the site. However, this failed and the relics of the martyr were apparently transferred to Santa Prassede in the 13th century.
The site was abandoned and forgotten, apart from an antiquarian investigation by Antonio Bosio in 1594, the record of which indicates that some walls of the church were still standing. The site began to be investigated archaeologically in 1877, when traces of the foundations were discerned and a painted underground room being used as a wine-cellar was noted. A crypt was dug out, and many carved marble fragments discovered then and during a second excavation in 1948.
The catacombs were accessible on three levels until 1986, when a landslide and flood trashed the whole site. At present, they are mainly either collapsed or in a dangerous state.
The complex is still advertised as open on one day a year, February 14th (St Valentine's Day), but this needs to be confirmed as it is also claimed by locals that the site is now never open.
Not all of the site was able to be excavated, but only the altar end of the basilica. It was shown that the edifice had a nave and aisles separated by columns, with apses at the ends of the aisles as well as a larger one behind the altar. The ends of the aisles also had a pair of staircases that ran down to a narrow transverse barrel-vaulted crypt that is parallel to the back wall of the basilica, and contains a cubical niche which lies under the main apse. It seems that this latter detail was where the shrine of the martyr was, and that pilgrims could file down one staircase and back up the other.