The Royal Basilica of San Isidoro in León hosts this festivity whose name comes from the three bows made by the city's representatives when they take their leave of the Chapter, and marks a tradition related to a miracle worked by Saint Isidore.

According to the Chronicon Mundi by Lucas de Tuy, in 1158 Saint Isidore caused it to rain over León. In gratitude, the city, represented by its Town Hall, every year convenes at the Basilica of San Isidoro to light one smaller and two large candles. In the cloister the Chapter accepts the gift, but makes it clear that this gift is compulsory. Due to this discrepancy, the representatives of both institutions embark on a dialectic battle. In the end, they declare a draw and the argument (which is actually the festivity) is postponed until the following year.