I was studying this festival when I came across some other festivals tied to it. But lets start with this festival, St. John's Day is celebrated on June 24. For some it includes singing songs and dancing until the sun sets, telling tales, searching to find the magic fern blossom at midnight, jumping over bonfires, greeting the rising midsummer sun. It is nominally a Christian feast day celebrating the birth of John the Baptist.
The Nativity of St John the Baptist is one of the oldest festivals, being listed by the Council of Agde in 506 as one of that region's principal festivals, where it was a day of rest and, like Christmas, was celebrated with three Masses: a vigil, at dawn, and at midday.
The Nativity of St John the Baptist on June 24 comes three months after the celebration on March 25 of the Annunciation, and six months before the Christmas celebration. They line up with the days related to the solstice.
The Nativity of John the Baptist are in fact more related to the celebration of midsummer which are themselves remnants of pagan midsummer festivals. The Midsummer Day festival was a pagan festival held on June 24 of each year, and Midsummer is one of the four pagan solar holidays, and church leaders wanted to Christianize the pagan solstice celebrations and for this reason advanced Saint John's feast as a substitute.
The four pagan solar holidays are Solar festivals which are the Winter Solstice (Yule) which is the shortest day, Summer Solstice (Midsummer) which is the longest day. The Spring Equinox and Autumn Equinox mark the time when hours of light and darkness are equal.
The Winter Solstice (Yule) festival is celebrated as the rebirth of the great god, who is viewed as the newborn solstice sun, and was the winter festival celebrated around the bonfires. It also is the pagan Roman solar holiday Dies Natalis Solis Invicti, the Sol Invictus ("Invincible Sun") was the official sun god of the later Roman empire which was picked up from pagan worship of Mithras. 'Sol ivictus' or better said as ';dies natalis solis invicti' is known as the festival of the unconquered sun. Since earliest history, the Sun was celebrated by pagans at the winter solstice when sun began it's journey into dominance after it's apparent weakness during winter. The origin of these rites, followers of Mithras believed, was a proclamation at the dawn of human history by the god Mithras commanding His followers to observe such rites on that day to celebrate the birth of Mithras, the Invincible Sun.
The Spring Equinox festival was characterized by the rejoining of the Mother Goddess and her lover-consort-son, who spent the winter months in death and has been connected to the goddess Eostre (Ishtar) the "goddess of sunrise" so we get the festival of Easter. In Deutsche Mythologie, Jacob Grimm speculates on the nature of the goddess....
"Eástre seems therefore to have been the divinity of the radiant dawn, of upspringing light, a spectacle that brings joy and blessing, whose meaning could be easily adapted by the resurrection-day of the christian's God. Bonfires were lighted at Easter and according to popular belief of long standing, the moment the sun rises on Easter Sunday morning, he gives three joyful leaps, he dances for joy...Water drawn on the Easter morning is, like that at Christmas, holy and healing.. "
The Summer Solstice or Midsummer Day was a festival celebrated as we saw by singing songs and dancing until the sun sets, telling tales and jumping over bonfires.
The Autumn Equinox festival was the marking of one of the points in the year when hours of light and darkness are equal but the dark is overcoming the light. It is also the time when leaves are falling from the trees, greenness is turning to brown as 'life' appears to be leaving the land. At this time many of the Pagan legends and myths are associated with descent into the Underworld.
Now we see how easily paganism crept into the church, the leaders allowed it and renamed the the pagan solstice celebrations
to bring them in... https://www.usatoday.com/story/news/2018/06/21/summer-solstice-celebration-facts-longest-day-year/721004002/https://www.bbc.co.uk/religion/religions/paganism/holydays/wintersolstice.shtmlhttps://www.worldreligionnews.com/religion-news/litha-pagans-celebrate-summer-solsticehttps://www.learnreligions.com/about-yule-rituals-2562970