Catacomb of Saint Thecla, Early Christian catacomb on Via Ostiense, Rome, Italy

The Catacomb of Saint Thecla lies along Via Silvio d'Amico in Rome's Ostiense quarter, cut into tufa rock. Its core is a small 4th-century underground basilica, built by enlarging a 3rd-century hypogeum cemetery, from which three wide ambulatories laid out as an isosceles triangle open onto 22 burial chambers. Twelve of these chambers were dug to a depth of three metres to fit extra loculi, and a single surviving light shaft comes from an old pagan mausoleum above.

The site dates back to the 3rd century when it served as a burial place for the early Christian community. A small underground basilica was built in the 4th century after important religious remains were transferred there.

The name Thecla links the site to a martyr of Iconium, though scholars debate whether she or a Roman woman executed under Diocletian lies here. A fresco with a woman at its centre is thought to show the buried Thecla. In 2009 and 2010 laser cleaning removed calcium deposits and revealed portraits of Peter, Andrew, John and Paul, held to be the earliest images of the apostles.

The catacomb lies along Via Silvio d'Amico in the Ostiense quarter, three kilometres south of the Aurelian Wall, near the Basilica of Saint Paul Outside the Walls. The underground galleries are reached by a staircase from the earlier building phases, and only one of the original light shafts, cut through pagan mausoleums above, still opens onto the corridors. Visits must be arranged in advance with the administration.

Twelve of the twenty-two burial chambers were filled to capacity: after cutting loculi into every wall of the roughly two-metre-high room, the fossors lowered the floor to three metres below the corridor level to open more graves in the side walls. This intensive burial is rare in Roman catacombs. The archaeologist Umberto Fasola also found that the site began as a pozzolana quarry and a dye works before becoming a cemetery in the 3rd century.