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Piece of wood kept in the Church of Santa Croce

The Titulus Crucis (Latin for "Title of the Cross") is a venerated piece of wood kept in the Church of Santa Croce in Gerusalemme in Rome which is claimed to be the [[Titulus (inscription) (title panel) of the True Cross on which Jesus Christ was crucified. It is venerated by some Catholics as a relic associated with Jesus. Its authenticity is disputed, with some scholars confirming a plausible authenticity, while others ignore or consider it to be a medieval forgery. Radiocarbon dating tests on the artifact have shown that it dates between 980 and 1146 AD. corresponding to John 19:19 and the initials INRI familiar to Roman Catholics. The Titulus Crucis is also mentioned in the Synoptics: in Mark 15:26 (as the reason of the crucifixion), in Luke 23:38 and in Matthew 27:37.

Saint Helena, Roman Empress and mother of Emperor Constantine the Great, went on pilgrimage to the Holy Land and reportedly discovered the True Cross and many other relics which were donated to the church of Santa Croce in Gerusalemme ("Holy Cross in Jerusalem") which she had built in Rome about AD 325. Gherardo Caccianemici dal Orso was made cardinal priest of the church in 1124 and, some time before he became Pope Lucius II in 1144, he renovated the church and had the relic deposited in a box that bears his seal as a cardinal. The box was apparently forgotten until 1 February 1492, when workers restoring a mosaic discovered it hidden behind a brick that was inscribed "Titulus Crucis".

Some Christian pilgrims who visited Jerusalem in the centuries between Helena and Pope Lucius reported seeing Christ's titulus there: Egeria reported that in AD 383 "A silver gilt casket is brought in which is the holy wood of the Cross. The casket is opened and (the wood) is taken out, and both the wood of the Cross and the title are placed upon the table." Antoninus of Piacenza in the 6th century described a titulus of "nut" wood with the inscription "Hic est rex Iudaeorum" ("Here is the king of the Jews"), corresponding to Luke 23:38.

In 1997, the German author and historian Michael Hesemann performed an investigation of the relic. Hesemann presented the inscription of the title to seven experts on Hebrew, Greek and Latin palaeography: Gabriel Barkay of the Israel Antiquities Authority, Hanan Eshel, Ester Eshel and Leah Di Segni of the Hebrew University of Jerusalem, Israel Roll and Benjamin Isaac of the University of Tel Aviv and Carsten Peter Thiede of Paderborn/Germany and the University of Beer Sheva, Israel. According to Hesemann, none of the consulted experts found any indication of a medieval or late antique forgery. They all dated it in the timeframe between the 1st and the 3rd–4th century AD, with a majority of experts preferring, and none of them excluding, the 1st century. Hesemann concluded that it is very well possible that the Titulus Crucis is indeed the authentic relic. Joe Nickell refers to this argument as "trying to psychoanalyze the dead," saying that "Forgers—particularly of another era—may do something cleverer or dumber or simply different from what we would expect." The Titulus Crucis recovered from the residence of Helena is therefore most likely a medieval artifact; an Italian classical scholar Maria Rigato discussed a possibility that it is a copy of the now lost original.