When Jesus was a baby, he, like every other Jewish boy, got his dick snipped. But because this was Jesus, his foreskin was way more special than your average foreskin; in fact, people thought it had magic powers. During the Middle Ages, there were numerous claims of people possessing the holy foreskin. At one point there were as many as 18 of them in existence, which would either mean Jesus had 18 penises and was some kind of hentai dick monster, or the foreskin of random non-Jesus babies were being pawned off as the legit wiener flesh of Christ.
For a while, the Holy Prepuce was apparently the gift to give, starting with Charlemagne giving it to Pope Leo III as a disgusting Christmas gift in 800 when the Pope crowned him Emperor. That one got stolen in 1527, because unlike Tickle Me Elmo, this was one popular Christmas gift that never came back in stock. Well, sort of. It was rediscovered in Calcata, Italy in 1557, and was authenticated by the Church's in-house CSI team.
In 1100, Baldwin I of Jerusalem brought a different (but presumably "legit") Jesus foreskin to Palestine during the first crusade. It went missing. Then it reappeared in the early 12th Century, then disappeared. Then re-reappeared in 1856. So either Jesus' foreskin can time travel, or everyone is a liar.