Rome's Layer Cake

The Basilica di San Clemente a few blocks from the Colosseum is the best place in Rome to see the layer-cake effect of its history in action, with church piled atop church piled atop pagan temple.

Nowhere else in this city is the layering effect of Rome's history more evident than in this 12th-century church built atop a 4th-century church built atop a late–2nd century pagan temple. This situation is far from unique in Rome—almost the entire city is built directly on top of the ancient one—but what's special about San Clemente is that you can actually clamber down into those lower levels to explore Rome's sandwich of history.

Even without that, the

upper church

—built in 1108 and run by the convent of Irish Dominican monks who rediscovered the lower levels in the 19th century—is beautiful enough to stand out on its own.

It features a

pre-Cosmatesque pavement,

ornate marble

choir

(a 6th– to 9th-century piece that came from the lower church), recently restored

frescoes of the Life of St. Catherine

(1228) by

Masolino

and his young disciple

Masaccio

in the first chapel on your right as you enter, and a

12th-century mosaic

filling the apse with a

Triumph of the Cross.

This mosaic shows a crucified Christ in the center with the Tree of Life growing in twisting vine tendrils all around, loaded with

medieval symbolism

(Christ and the Apostles pose as sheep along the bottom, the Rivers of Paradise flow from the base of the cross from which the faithful, represented by stags, drink, doves flutter about, and the Hand of God reaches down from the canopy of the Heavens).

Off the right aisle is a postcard-lined passageway and the entrance down to the

lower church,

built in the 4th century and largely demolished by Barbarian sackings in 1084. It preserves a few crude

frescoes,

including the Life of St. Clement on the wall before you enter the nave and the Story of St. Alexis on the left wall of the nave itself.

After you've had your fill of this

Dark Ages church,

you can descend another flight of stairs to the

ancient pagan Mithraic temple

and adjacent

Roman palazzo

of the AD 1st century. The altars of both later churches are placed directly above this

pagan altar to Mithras,

which depicts the god sacrificing a bull. (As part of their rituals, Mithraic priests would also sacrifice bulls until the blood flowed into troughs, which followers would then scoop out with their arms to bathe in; sounds nasty, but back in the day it was a hugely popular cult—certainly it had far more acolytes in the first few centuries AD than another of the many nascent cults swirling around Imperial Rome: Christianity.)

As you wander in and out of the brick vaulted rooms of

Flauvius Clemens' grand palazzo,

you'll hear the sound of rushing water from the

ancient pipes and aqeducts

between the walls. In one room you can even take a drink from the sweet spring water gushing out of an ancient pipeline to be routed along a small aqueduct set into the wall.

Via San Teodoro, but entrance on Via San Giovanni in Laterano, two long blocks southeast of the Colosseum.
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