The Jewish High Holy Day Prayer Kol Nidrei is traditionally seen as one of the most important prayers of the year.
Kol Nidrei goes back to the days of the Spanish Inquisition, when the conversos (Jews who chose to convert to Christianity rather than face expulsion or death, but remained faithful to Judaism at heart, and to some degree in observance too) would gather on Yom Kippur eve in their hideout synagogues.
The popular version connects the wording of the prayer with the religious dilemma facing medieval Spanish Jews. In 15th-century Spain, at the hight of the infamous Inquisition, the Roman Catholic Church embarked on a determined hunt to seek out and punish all non-practicing Christians. For the majority of Jews their “conversion” was in name only as they still found creative ways to practice Judaism in the privacy of their own dwellings. These Jews came to be known as “marranos” and became one of the foci of the Church’s inquistory offensive.
The Kol Nidre prayer was created in response to these Jews’ desire to nullify their vows of conversion. We can see the potential validity of this historical claim in a literal translation of Kol Nidre:
“All vows and oaths we take, all promises and obligations we made to God between this Yom Kippur and the last we hereby publicly retract in the event that we should forget them, and hereby declare our intention to be absolved of them.”