The Holy Prepuce, or Holy Foreskin (Latin præputium or prepucium), is one of several relics attributed to Jesus, consisting of the foreskin removed during the circumcision of Jesus. At various points in history, as many as 31 churches in Europe have claimed to possess the Prepuce, sometimes at the same time. Various miraculous powers have been ascribed to it, such as claims the relic has the power of duplication according to David Farley.

All Jewish boys are required by Jewish religious law to be circumcised on the eighth day following their birth; the Feast of the Circumcision of Christ, still celebrated by many churches around the world, accordingly falls on January 1. Luke 2:21 (King James Version), reads: "And when eight days were accomplished for the circumcising of the child, his name was called JESUS, which was so named of the angel before he was conceived in the womb." The first reference to the survival of Christ's severed foreskin comes in the second chapter of the apocryphal Arabic Infancy Gospel which contains the following story:

And when the time of his circumcision was come, namely, the eighth day, on which the law commanded the child to be circumcised, they circumcised him in a cave.

And the old Hebrew woman took the foreskin (others say she took the navel-string), and preserved it in an alabaster-box of old oil of spikenard.

And she had a son who was a druggist, to whom she said, "Take heed thou sell not this alabaster box of spikenard-ointment, although thou shouldst be offered three hundred pence for it."

Now this is that alabaster-box which Mary the sinner procured, and poured forth the ointment out of it upon the head and feet of our Lord Jesus Christ, and wiped it off with the hairs of her head.

Foreskin relics began appearing in Europe during the Middle Ages. The earliest recorded sighting came on December 25, 800, when Charlemagne gave it to Pope Leo III when being crowned Emperor. Charlemagne claimed that it had been brought to him by an angel while he prayed at the Holy Sepulchre, although a more prosaic report says it was a wedding gift from the Byzantine Empress Irene. Its authenticity was later considered to be confirmed by a vision of Saint Bridget of Sweden, who confirmed that it was somewhere in Rome. The Descriptio Lateranensis Ecclesiae, written shortly before 1100, indicated that a cypress chest commissioned by Leo III and placed under the altar in the Chapel of St. Lawrence held three caskets. One of the caskets contained a gold jeweled cross. The document stated that in this cross was the foreskin and umbilicus of Jesus.

However, in 1905 Pope Pius X authorized an inventory compiled by Professor Hartmann Grisar, of the University of Innsbruck. Grisar's report corresponds to the earlier Descriptio Lateranensis Ecclesiae. The gold cross was dated to between the sixth and eighth centuries. Grisar's study stated that, like Pope Paschal's enameled silver reliquary cross, the gold jeweled cross was clearly initially designed to hold a relic of the True Cross. This is further supported by the statement in the Descriptio relating it to a procession on the feast of the Exaltation of the Holy Cross. The Vita of Pope Sergius I (687-701) mentions both the Feast of the Exaltation, the jeweled cross, and veneration of the relic contained therein. Grisar attributed the reference to the foreskin and umbilicus as derived from later Medieval traditions. The gold cross was lost in 1945.