The basilica is dedicated to the honour of the deacon and martyr, St. Lawrence, who was martyred in the persecutions of the Emperor Valerian in the year 258. St. Lawrence has been an important saint to the Romans for some time and in fact is second only to Ss. Peter and Paul in patronal importance to the city, being considered the third patron of Rome.
Of the five papal basilicas of Rome, San Lorenzo is that which best retains its most historically antique form -- closely followed by the other papal basilica outside the city walls, San Paolo -- though while that venerable basilica is certainly early in its basilica form of course, much of the actual architectural structure is now a nineteenth century reconstruction as a result of a disastrous fire that occurred in that century that destroyed approximately two thirds of it (fortunately the apse itself was part of what was spared).
 |
| San Paolo fuori le mura after the fire of 1823 |
Returning to San Lorenzo, it too has suffered destruction in the course of it its history, in this case much more recently as a result of an inadvertent Allied forces bombing that took place during the Second World War, resulting in the destruction of much of the portico and facade. Here was how it looked prior to 1943:
.jpg)
As is the case of many Roman basilicas, there is a portico. This also dates to this latter this period and within are various spolia as well as medieval wall frescoes depicting scenes from the life of St. Lawrence and St. Stephen -- both of whom were deacons and martyrs, and both of whom are buried within the basilica (the relics of the latter having been brought from Constantinople to Rome).
As we move into the basilica proper, we are greeted first by the long nave that forms the newer, Honorian part of the basilica which, as mentioned, is dated to the thirteenth century. It includes beautiful cosmatesque, polychrome pavement and is lined by Ionic columns.
As one approaches the altar and presbytery, one will see the medieval lectern and ambo that would be historically used for the epistle and gospel respectively.
 |
| The lectern |
 |
| The ambo is particularly impressive and follows a fairly typical form for this period |
 |
| The ambo seen from the outer aisle/nave. Stairs are found on both sides, thus facilitating the gospel procession. |
This brings us to the triumphal arch, leading us toward what was the earlier Pelagian basilica. Just in front of where this triumphal arch is (from this vantage point) was the former apse of Pelagius' sixth century basilica.
One will note the typical, open-timber, trussed ceiling in the basilica. In the later medieval and renaissance period, like many of the Roman basilicas, a decorative, coffered ceiling had been put in place in this basilica as well, but this was removed in the nineteenth century as a result of the medievalism that was prominent during that time. A sense of what was there before this can be seen in this engraving from 1809:
One will also note here that the former of the top of the ciborium magnum is also different, being of a renaissance style. This was also replaced in the nineteenth century.
It is also worth noting that while the walls are now plain brick, prior to the inadvertent bombing of the basilica in 1943, the walls were covered with various painted scenes:
The mosaics on the triumphal arch are worth your attention. That facing the nave is of more modern vintage, but that located on the side of the old Pelagian basilica (i.e. where the altar and presbytery are located) is dated to the sixth century and includes an image of Christ enthroned, surrounded by Ss. Peter and Paul, Ss. Lawrence and Stephen, and then also Pope Pelagius (the founder of the present basilica, thus holding a model of the church) and St. Hippolytus. These would have originally faced toward the nave and congregation in the original basilica's orientation; they now face the presbytery.
 |
| Christ surrounded by Ss. Peter and Paul |
 |
| The basilica's saintly patron, St. Lawrence, and its architectural patron, Pope Pelagius |
Turning our attention now the present day presbytery, this was raised in the thirteenth century, having originally been at the same level as the floor of the confessio where the remains of St. Lawrence and St. Stephen are buried (seen here beneath the high altar with its ciborium). One will also note the semi-circular pavement. This demarcates the location and shape of the original apse of Pelagius' basilica.
The altar and the lower portion of the ciborium dates to the eleventh century and is the work of the Cosmati family, being actually "signed" by them (i.e. their names are inscribed/etched into it). As mentioned previously, the top portion of the ciborium was originally a domed, renaissance replacement (looking very much like the dome of the duomo of Florence) which was installed after a portion of the ceiling collapsed, seriously damaging part of the earlier, medieval ciborium. This dome would be replaced in the nineteenth century with something more consistently medieval in form and design.
 |
| One will also note here the rather architecturally odd appearance of the truncated columns located within this section of the basilica. This, of course, is due to the fact that this section was raised later. Behind those columns are now walkways going down to the original floor level of the original basilica. |
 |
| The cathedra |
