I am adapting the following from a column I published at real clear religion, back in 2013.
Many of the events in the Christian liturgical year coincide with older seasonal celebrations, which the church absorbed and consecrated. We think of Christmas (Midwinter), Easter (Spring) and All Saints/All Souls (the beginning of Winter). Generally, Western churches at least have forgotten what was once one of the greatest of these parallel commemorations, which almost amounted to a second Christmas. Somewhere along the line, we forgot St. John the Baptist.
For the early church, John the Baptist was clearly a critical figure. In fact, New Testament writers had to argue against those who saw him as at least comparable to Jesus. He was reputedly a blood relative of Christ himself. Not surprisingly, then, the later church made him a mighty hero of the faith, and built him into its emerging calendar. But when you did that, the Biblical evidence pointed to an interesting correlation with Christ’s own career. If John’s mother was in her sixth month when Mary conceived (Luke 1.36), then presumably John was born half a year later than his cousin. As the church increasingly associated Jesus’s own birth with Midwinter, then inevitably, John’s must have fallen at Midsummer. Hence his nativity became fixed at June 24.
As the church expanded into pagan Europe, that Midsummer connection added enormously to popular devotion to John. As the high point of the solar calendar, and the longest day, Midsummer was a widely beloved festival. It was associated with many popular customs and rituals, mainly marked by fire but also by ritual washing in rivers. Bonfires burned to ward off evil forces and defeat witches, while women collected medicinal plants and ferns. The fires became the focus of dancing and leaping, while wheels were rolled to symbolize the sun’s progress. As a day when boundaries between the worlds were thought to be thinnest, it was also a natural time for divination. (St. John’s Day is close to the summer solstice, but not an exact match. This year, the Solstice fell on June 21, ie yesterday).
In Christian times, these customs became firmly attached to St. John’s Eve, June 23. Among many other survivals, that is why the plant became St. John’s Wort, while St. John’s Fires burned on the hillsides. Still in northern Europe, St. John’s Eve remains one of the very greatest moments of the year, paralleled only by Christmas. It has a comparable significance in other regions in Québec, where the linkage to fires and fireworks remains strong. Just as the evening before All Saints (All Hallows) became Halloween, so St. John’s Eve served as a focus for elaborate merry-making, for parades and pageantry.
The church struggled long and hard against other customs that it could neither absorb nor tame. Residual pagan connotations were potent in Russia, where they supplied the foundation for Nikolai Gogol’s 1830 masterpiece “St. John’s Eve.” This phantasmagoric tale describes the bizarre happenings in a small village on that enchanted evening, with all its encounters with witches and demons, as inanimate objects spring to life. Even those who have never read the story have encountered its musical aftermath. Gogol’s tale is the inspiration for Mussorgsky’s tone poem St. John’s Night on the Bare Mountain, which Rimsky-Korsakov reworked under the title Night on the Bare Mountain. This achieved popular fame worldwide through Disney’s Fantasia (and even featured as a disco version in Saturday Night Fever).
Through the Middle Ages, the churches treated St. John’s Nativity as a duplet of Christmas. If it wasn’t for the painful association with the name of Antichrist, it would be tempting to refer to the day as “Anti-Christmas.” It was a day of special vigils and multiple masses, each with its special symbolism. A vigil mass at night suggested John’s role as fore-runner; one in the morning recalled his role as baptizer; a third marked his special sanctity. Relics of St. John were prized as much as those of any saint. To the scandal of the church’s intellectuals, multiple centers claimed the Baptist’s head.
Christians also rejoiced in the day’s older connotations. Like earlier pagans, they were well used to using light and fire as symbols of holiness and truth, as when they lit the Paschal Candle to celebrate Christ’s Resurrection at Easter. They found no embarrassment whatever in lighting bonfires to consecrate the landscape to John, and more especially to Christ, the true Light. They even found scriptural justification for the Midsummer/Midwinter parallel, and its solar context. Had not the John of the New Testament proclaimed that “He must increase, and I must decrease”? That is what the sun appeared to do during the year.
So rich is the imagery that it is surprising that St. John’s Day is not better known among Western churches, even among liturgically-oriented communities. Why don’t we have Midsummer fires? The day is too important to be left to the pagan revivalists.
I also have a final story that seems too good to be true, but this is multiply attested in worthwhile sources.
One popular hymn for the feast of St John’s Eve was Ut queant laxis, composed by Paul the Deacon in the eighth century. Because it uses successive notes of the scale, it proved very useful for teaching music. In the eleventh century, musical theorist Guido of Arezzo named the notes by taking the first syllable of each word, as follows:
Ut queant laxis
He ended up with Ut-Re-Mi-Fa-Sol-La-Si. The final Si stood for Sanctus Iohannes, St. John.
The details have changed somewhat over the century, so that Ut became Do, but basically that is where we get our Do-Re-Mi.