With K's permission:
(Background information for non-English buffs: Before inventions like printing presses, all books had to be hand copied. In times before paper, books were written on thin animal hides with ink. If you made a mistake while writting (white-out not being an option), you scarped off the first layer of skin to remove the ink. As you can tell books back then cost a good deal of money and most people that had 1000s of hours on their hands to make books were the more religious types.)
Teh joke: One day a young scholar decided to visit the Vatican because he was bothered by the accuracy of translated texts. He was speaking privately to the priest about his concerns.
"Father, I just dont think that ever word could have been written down exactly as it was first scribed. Not after several hundreds of years and several different monks making copies."
The Father assured him that the priesthood takes great pride in exactly every word being identical as the original. To prove his point, he offered to let the young scholar view the original copy of the church rules (on of the few originals they still had on the grounds) and today's version.
The Father stepped back into the archive room and left the young scholar to wait in the library for him. The scholar waited....waited.....waited... seems that the priest had gotten lost at this point. When all of the sudden he heard someone crying out in great agony.
The scholar jumped up and ran in the direction of the noise. When he arrived, he saw the priest curled into a ball rocking back and forth making a horrible pained noise.
"What's wrong, Father?"
"It said 'Celebrate.'"