Titulus Crucis

Titulus Crucis (Latin for "Title of the Cross") is a piece of wood kept in the Church of Santa Croce in Gerusalemme in Rome which is claimed to be the "titulus" (title panel) of the True Cross on which Jesus was crucified. It is venerated by some Catholics as a relic associated with Jesus. It is generally either ignored by scholars or considered to be a medieval forgery.
The board is made of walnut wood, 25 × 14 × 2.6 cm (10 × 4½ × 1 in) and has a weight of . It is inscribed on one side with three lines, of which the first is mostly destroyed. The second line is written in Greek letters and reversed script, the third in Latin letters, also with reversed script. The Latin reads ("Jesus the Nazarene King of the Jews"), corresponding to and the initials INRI familiar to Roman Catholics. The Titulus Crucis is also mentioned in the Synoptics: in (as the reason of the crucifixion), in and in .
Helena's relic.
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". It was the same day that news reached Rome of the downfall of the Moors in Spain. Pedro González de Mendoza, Spanish cardinal priest of Santa Croce at the time, encouraged veneration of the rediscovered relic.
Other Jerusalem relics.
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 . 
Authenticity.
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 mediaeval 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.
Carsten Peter Thiede suggested that the "Titulus Crucis" is likely to be a genuine part of the Cross, written by a Jewish scribe. He cites that the order of the languages match what is historically plausible rather than the order shown in the canonical New Testament because had it been a counterfeit, the forger would surely have remained faithful to the biblical text. 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."
In 2002, the Roma Tre University conducted radiocarbon dating tests on the artifact, and it was shown to have been made between 980 and 1146 AD. The uncalibrated radio-carbon date was 1020 ± 30 BP, calibrated as AD 996–1023 (1σ) and AD 980–1146 (2σ), using INTCAL98. These results were published in the peer-reviewed journal "Radiocarbon". 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.