When the Catholic Church’s Inquisition came to Spain in the 15th Century, they gave people of the Muslim or Jewish religions a simple choice: Give up their Muslim or Jewish religion or die; convert to Roman Catholicism or leave Spain. There was some stealing and torture and other horrible things but, well, Muslims had ruled the land for around 500 years, sometimes with Jewish help, and people were scared they might return.
One Jew, his family having lived in Spain keeping the Jewish faith for almost 2000 years--longer even than the Catholic Church or Islam existed, let alone been in Spain –discussed matters with his wife and they decided not to leave their home. The family would become Catholic.
Every day for months the man studied with a Catholic Priest. He learned the prayers, the traditions. On Friday, the Catholics ate no meat, to honor the death of the God they named Jesus Christ. On Sundays, the man and his family prayed in Church and took sacrament, the bread which they were told had magically transubstantiated into the body of Christ. The choir sang beautiful songs in a Church with high ceilings; the Priests wore gorgeous robes of fine silk; they worshiped the Cross and its crucified Christ, which had unmistakable gravity. And by the third month, the Priest was pleased to see that the man, of his own volition, even made donations.
At the end of each lesson, the man would kneel fealty to the Priest . The Priest would put his hand on the man’s head and chant, “You once were a Jew, Now you are a Catholic! Once you were a Jew, now you are a Catholic!”
The Priest, Catholic though he might be, was a good man and the former Jew liked him. “Once I was a Jew, now I am a Catholic,” the man would happily reply, his head bowed.
He was a good learner, earnest, and prayed for the day he could say the phrases in Latin and truly understand the Catholic mass.
Several months passed. One Friday the Priest decided to check on the man to see if he and his family were really Catholic. The Priest went to the man’s house fearing the worst. But the man came quickly to the door, opened it, and greeted the Priest with a big hug.
“Father, Father, I am so glad you came! I love being a Catholic! So does my wife! You must stay for dinner!”
“You love being a Catholic,” the Priest chuckled.
“Yes,” the man said proudly, “I love the robes and the songs and the devotion of the Congregation, the love overwhelms us! It will be even better once I learn Latin! And Christ! I have taken him to my heart as my lord and savior!”
“Good,” the Priest said, “that is well, my son.”
“And, well, maybe I should not tell you this. My wife says we should have joined long ago. You see, the Catholic Church donations are less than what our Rabbi used to demand.”
The Priest was still in the man’s hug and did not know what to say. The man’s little boy, just turned four, wandered in. “Can Father Catholic stay for dinner,” the little boy asked.
“Stay for dinner please, Father” said the man urged. “My wife is cooking our favorite dish, Chicken!”
And the Priest suddenly realized he smelled chicken cooking.
“It’s Friday,” the Priest exploded, “You stupid Jew! You heathen! We Catholics eat fish on Friday! Fish! To honor Christ!”
“Catholic, Father,” the man said smiling, taking the Priest’s arm to lead him to dinner. “I am Catholic not a Jew. There is no problem. I remember my lessons.
"Friday is fish day. So I put my hand on the chicken’s head and told it “Once you were a chicken, now you are a fish! Once you were a chicken, now you are a fish!”
The Roman Catholic Church is known as Mother Church. For good reason. Its been dominant since around 300 AD, the Council of Nicea and all that.
Christianity as most should know is a syncretic religion. That is, it borrowed from other religions. How much and from who people are still arguing over; different Christian sects usually have a regional bias.
But one source of course is the Hebrews. The first Christians were all Jews, including Christ.
In the fight over what went into the books we now call the Bible, the early Catholic Church chose several of the Hebrew texts.
It the RCC is Mother Church, then it seems to me appropriate to coin a name for the Jewish religion: Grandpa Church.
The joke is an old Jewish Marano joke, dating back 500 or so years.
The maranos were Jews living in Spain or Portugal who converted to Catholicism under the duress of the Roman Catholic Inquisition. Some secretly kept their Jewish faith; some kept old traditions; but no one could change their blood. Anyone could be picked on by the Inquisition and so it went. The source of the term "marano" is disputed but it probably comes from "pig" or from same the root of "anathema." It was hurled by Catholics as an insult and worn by Jews who escaped the Inquisition as a badge of honor.
Thing is, there have been times and places when telling this joke would get you killed. Spain in 1300-1500. That's partly why its funny.
The Jews called themselves maranos because they were always a minority group in Spain. They had worked with the Muslim leaders (some of those were not so bad, some of those were quite like the Catholic Inquisition) but also worked with the Christian leaders as well.
I read the joke came from one of Professor Goldstein's books on Spinosa.
This joke can be a test. Tolerant Roman Catholics, the liberal wing, laugh and think it hilarious. But tell it to one of the muscular Catholics, the more superstitious kind. They don't get it. If you explain to them the joke, they get very offended.