Stolen From Simply Jews
There are many rituals in accordance with tradition, but there is one tradition that very few people know about.
Shortly after a new Pope is enthroned, the Chief Rabbi of Rome seeks an audience. He is shown into the Pope's presence, whereupon he presents the Pope with a silver tray bearing a velvet cushion. On top of the cushion is an ancient, shriveled envelope. The Pope symbolically stretches out his arm in a gesture of rejection. The Chief Rabbi then retires, taking the envelope with him and does not return until the next Pope is elected.
A new Pope's reign was shortly followed by a new Chief Rabbi. He was intrigued by this ritual and that its origins were unknown to him. He instructed the best scholars of the Vatican to research it, but they came up with nothing.
When the time came and the Chief Rabbi was shown into his presence, they faithfully enacted the ritual rejection but, as the Chief Rabbi turned to leave, the Pope called him back.
"My brother," the Pope whispered, "I must confess that we Catholics are ignorant of the meaning of this ritual enacted for centuries between us and you, the representative of the Jewish people. I have to ask you, what is it all about?"
The Chief Rabbi shrugged and replied: "We have no more idea than you do. The origin of the ceremony is lost in the traditions of ancient history."
The Pope said: "Let us retire to my private chambers and enjoy a glass of kosher wine together; then with your agreement, we shall open the envelope and discover the secret at last." The Chief Rabbi agreed.
Fortified in their resolve by the wine, they gingerly pried open the curling parchment envelope and with trembling fingers, the Chief Rabbi reached inside and extracted a folded sheet of similarly ancient paper.
As the Pope peered over his shoulder, he slowly opened it. They both gasped with shock —
It was a bill for the Last Supper — from "Moishe the Caterer."
Remark: that joke is probably as old as Papacy, but right now it's relevant again, for a while...