The current festival takes it origin from the Scottish and Irish Gaelic pre-Christian May Day festival. It was usually held halfway between the spring equinox and the summer solstice. According to some sources, the blooming of the hawthorn was the primary sign for the event.

The festival was a celebration of the fertility of their lands and cattle, and coincided with the moving of their animals to the summer pastures. The central element of the festival was the fire, which also gave it its name – the Gaelic-Celtic word beltane means ‘sacred fire’. First, all the fires in the community were extinguished and then a new sacred ‘Neid Fire’ was lit by the village leader. From this source, two bonfires were started and the animals of the community were driven between them. It was believed that the smoke and flame of the fires would purify the herd, protecting them in the year to come and ensuring virility. The villagers also took embers from the sacred fire to relight their fireplaces and then danced clockwise around the fire to bring good luck to their families.

The contemporary Beltane Fire Festival in Edinburgh is a revival of this ancient Gaelic tradition, first held in 1988. Since then, it has become the largest fire festival of its kind. On the night of the fiery celebrations, quirky characters parade and dance to the beat of pounding drums and in the light of fluttering flames. The Beltane Fire Festival features a number of characters, some traditional and some modern.

The procession is led by the May Queen. She represents purity, strength and the potential for growth. She is the embodiment of the earth’s energy and encompasses everything. The May Queen’s consort is the Green Man. Dressed in ivy, leaves and flowers, he represents the living spirit of spring vegetation. At the beginning of the festival, he appears in the form of a Horned God. Directly behind them in the procession are the White Women,headed up by the Queen’s four Handmaidens (North, South, East and West). The white women are the warriors who guard and take care of the May Queen, and they represent order and discipline. The procession is accompanied by drummers and torchbearers. Their journey is interrupted by various groups who either help or hinder their progress towards the Green Man’s fate and the May Queen’s destiny. Notably, the Red Men and the Red Beastie Drummers try to disrupt the procession with their lewd and lascivious behavior. Their energy is rooted in rebirth, and they bring chaos and disorder.

The procession begins at the National Monument (known to Beltaners as the Acropolis) and proceeds counterclockwise on the path through the Fire Arch, a gateway into the Other World – a place where things are fractured into their separate elements. As the procession passes through the Other World, they visit the four classical elements of nature. The Air Point represents the characteristics of wind, air and communication. Air can be gentle and ethereal, but also powerful and dangerous. The Earth Point represents the entire world, including mountains, forests and living creatures. The Water Point represents the various aspects of water and also focuses on its cleansing and purifying role. Water is necessary for all forms of life, but it can also be powerful and violent. Finally, the Fire Point represents the warmth of the spring sun and also focuses on the fire’s purifying role. Fire gives light and warmth, but it can also devour everything.

The procession is followed by a dramatic ritual led by the Blue Man, who are the elders of the Queen’s court. First, the Green Man (still in the form of the Horned God) touches the May Queen and dies instantly. The queen’s Handmaidens immediately begin to tear off his garments. Then, the Queen breathes life back into him and he is reborn as the youthful Green Man. They spark the birth of summer by lighting a huge bonfire. At the end of the evening, all the participants gather at the place called Bower.

Sources
https://beltane.org/about-beltane/