They have their origins instead in a Medieval hymn sung on the Solemnity of the Nativity of St. John the Baptist, which, incidentally, happens to be today.
Here are two versions of said hymn:
About this day, St. Augustine wrote:
The Church observes the birth of John as a hallowed event. We have no such commemoration for any other fathers; but it is significant that we celebrate the birthdays of John and of Jesus. This day cannot be passed by. And even if my explanation does not match the dignity of the feast, you may still meditate on it with great depth and profit. John appears as the boundary between the two testaments, the old and the new. That he is a sort of boundary the Lord himself bears witness, when he speaks of “the law and the prophets up until John the Baptist.” Thus he represents times past and is the herald of the new era to come. As a representative of the past, he is born of aged parents; as a herald of the new era, he is declared to be a prophet while still in his mother’s womb. For when yet unborn, he leapt in his mother’s womb at the arrival of blessed Mary. In that womb he had already been designated a prophet, even before he was born; it was revealed that he was to be Christ’s precursor, before they ever saw one another. These are divine happenings, going beyond the limits of our human frailty. When John was preaching the Lord’s coming he was asked, “Who are you?” And he replied: “I am the voice of one crying in the wilderness.” The voice is John, but the Lord “in the beginning was the Word.” John was a voice that lasted only for a time; Christ, the Word in the beginning, is eternal.
According to Fr. Z, the traditional celebration involved the above hymn, a bonfire sprinkled with holy water, and (in Rome) a feast of snails. Who knew escargot had a place in the liturgical calendar?
head on over to Catholic Culture.