The most striking relic is the Titulus Crucis, a fragment of walnut or poplar board about 25 centimetres wide bearing part of an inscription. The Gospels record that Pilate had a charge fixed above the cross, "Jesus of Nazareth, King of the Jews", written in Hebrew, Greek and Latin, and the Santa Croce board carries remnants of the words in all three scripts, the Greek and Latin lines running unusually from right to left.
The panel was found on 1 February 1492, sealed inside a niche behind a mosaic near the top of a triumphal arch, where an inscription of 1143 recorded it had been hidden. Believers take it for the actual titulus of the crucifixion. A radiocarbon test published in 2002 dated the wood to roughly the tenth to twelfth centuries, which would make it a medieval object; supporters argue the sample may reflect later handling or that the board is a faithful medieval copy of a lost original. The Church venerates it without pronouncing on the scientific question, and it remains the centrepiece of the Chapel of the Relics.