Eamon Duffy, Professor of the History of Christianity in the University of Cambridge, is the author of the splendid study, Saints and Sinners: A History of the Popes, now newly updated.

As Commonweal readers know, he also has a fine collection of essays, entitled Faith of Our Fathers: Reflections on Catholic Tradition. The book elicited a lively exchange in Commonweal (March 11, 2005) between the author and four commentators.

One of my favorite passages in the book reads:

I am fond of the analogy between tradition and one building in particular, the church of San Clemente in Rome, near the Colosseum.

[T]he glory of the apse is its glittering twelfth-century mosaic, a crucifixion in which Christ is surrounded on the cross by doves, while the cross itself rises from a luxuriant blue and green tree of life. From it flow streams of water, from which thirsty deer drink. In its shelter animals and birds feed and play, the weapons of war lie discarded, and human life goes on -- a woman throws corn to her chickens, a shepherd tends his seep.

The San Clemente mosaic is a theology in itself. But it is only the start of what the building has to offer.

Duffy then goes on to describe how, in the nineteenth century, excavations were begun which uncovered under the present basilica, the original (and larger) basilica, dating from perhaps the fourth century. Still not content, the prior of the Irish Dominicans, who have cared for the church since the seventeenth century, insisted, to the consternation of the brethren, that the digging continue. What they discovered under the original basilica was a first-century Roman street, with what may be the original house of St. Clement, alongside a temple to Mithras.

Reflecting upon the complex reality, Duffy muses:

For me, San Clemente is a near-perfect expression of Catholic tradition, layer upon layer of shared prayer, thought, sufferings -- and sin. Like the mosaic, the church yields its meaning only to slow meditation and close attention to the traces of the past which it contains, some of it half-buried and forgotten ... [Traditon] is able to surprise and shock us, as well as confirm in us what we already knew; it is able to stop us in our tracks and think again, and able always to make us catch our breath with its sheer majesty and beauty.

I have the immense good fortune of being able, when visiting Rome, to stay near San Clemente. I always make a visit to the church the first thing I do upon arrival, in order to pray before the cross of Christ as tree of life. I am awed to think that perhaps Francis of Assisi or Thomas Aquinas prayed here. And I always light a candle for relatives and friends, colleagues and students. Since I will leave for Rome in a few days, be assured that you also will be remembered in the flickering flame.