The name itself is thought to have derived from a Gaelic-Celtic word meaning ‘bright/sacred fire’. It was held to mark and celebrate the blossoming of spring, and coincided with the ancient pastoral event of moving livestock to their summer grazing. It did not occur on any fixed solar date (the tradition of solstices and equinoxes is later in origin) but tended to be held on the first full moon after the modern 1st of May. Some sources suggest that the blooming of the Hawthorn was the primary signal for the event before the development of centralised calendars.
As an ancient Gaelic festival, Bealtaine was celebrated in Ireland, Scotland and the Isle of Man, though there were similar festivals held at the same time in the other Celtic countries of Wales, Cornovii areas of England, Brittany and Cornwall. Bealtaine and Samhain were the leading terminal dates of the civil year in Ireland though the latter festival was the more important. The festival survives in folkloric practices in the Celtic Nations and the Irish diaspora, and has experienced a degree of revival in recent decades. In Wales, the day is known as Calan Mai, and the Gaulish name for the day is Belotenia.
It was a celebration of the fertility of the land and their animals. The main traditional element which was common to all Beltane festivals was the fire which gave it its name. All the fires of the community would be extinguished and a new, sacred ‘Need Fire’ was lit by either the village head or spiritual leader. From this source one or two bonfires were lit, and the animals of the community would be driven through or 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 a good number of offspring. The inhabitants of the village would then take pieces of the fire to their homes and relight their hearths, and dance clockwise around the bonfires to ensure good portents for them and their families.
For the Celts, Beltane marked the beginning of the pastoral summer season when the herds of livestock were driven out to the summer pastures and mountain grazing lands. Due to the change from the Julian calendar to the Gregorian calendar, Bealltainn in Scotland was commonly celebrated on May 15 while in Ireland Sean Bhealtain / "Old May" began about the night of May The lighting of bonfires on Oidhche Bhealtaine ('the eve of Bealtaine') on mountains and hills of ritual and political significance was one of the main activities of the festival.
In modern Scottish Gaelic, Latha Buidhe Bealltainn or Là Buidhe Bealltainn ('the yellow day of Bealltain') is used to describe the first day of May. This term Lá Buidhe Bealtaine is also used in Irish and is translated as 'Bright May Day'. In Ireland it is referred to in a common folk tale as Luan Lae Bealtaine; the first day of the week (Monday/Luan) is added to emphasise the first day of summer.
In ancient Ireland the main Bealtaine fire was held on the central hill of Uisneach 'the navel of Ireland', one of the ritual centres of the country, which is located in what is now County Westmeath. In Ireland the lighting of bonfires on Oidhche Bhealtaine seems only to have survived to the present day in County Limerick, especially in Limerick itself, as their yearly bonfire night and in County Wicklow in Arklow, though some cultural groups have expressed an interest in reviving the custom at Uisneach and perhaps at the Hill of Tara.
The lighting of a community Bealtaine fire from which individual hearth fires are then relit is also observed in modern times in some parts of the Celtic diaspora and by some Neopagan groups, though in the majority of these cases this practice is a cultural revival rather than an unbroken survival of the ancient tradition.
Another common aspect of the festival which survived up until the early 20th century in Ireland was the hanging of May Boughs on the doors and windows of houses and the erection of May Bushes in farmyards, which usually consisted either of a branch of rowan/caorthann (mountain ash) or more commonly whitethorn/sceach geal (hawthorn) which is in bloom at the time and is commonly called the 'May Bush' or just 'May' in Hiberno-English. Furze/aiteann was also used for the May Boughs, May Bushes and as fuel for the bonfire. The practice of decorating the May Bush or Dos Bhealtaine with flowers, ribbons, garlands and colored egg shells has survived to some extent among the diaspora as well, most notably in Newfoundland, and in some Easter traditions observed on the East Coast of the United States.
Bealtaine is a cross-quarter day, marking the midpoint in the Sun's progress between the spring equinox and summer solstice. Since the Celtic year was based on both lunar and solar cycles, it is possible that the holiday was celebrated on the full moon nearest the midpoint between the spring equinox and the summer solstice. The astronomical date for this midpoint is closer to May 5 or May 7, but this can vary from year to year.
Place names in Ireland that contain remnants of the word 'Bealtaine' include a number of places called 'Beltany' - indicating places where Bealtaine festivities were once held. There are two Beltanys in County Donegal-- one near Raphoe and the other in the parish of Tulloghobegly. Two others are located in County Tyrone, one near Clogher and the other in the parish of Cappagh. In the parish of Kilmore, County Armagh, there is a place called Tamnaghvelton/Tamhnach Bhealtaine ('field of the Bealtaine festivities'). Lisbalting/Lios Bealtaine ('fort or enclosure of Bealtaine') is located in Kilcash Parish, County Tipperary. Glasheennabaultina ('the Bealtaine stream') is the name of a stream joining the River Galey near Athea, County Limerick.
In Irish mythology, the beginning of the summer season for the Tuatha Dé Danann and the Milesians started at Bealtaine. Great bonfires would mark a time of purification and transition, heralding in the season in the hope of a good harvest later in the year, and were accompanied with ritual acts to protect the people from any harm by Otherworldly spirits, such as the Aos Sí. Like the festival of Samhain, opposite Beltane on October 31 Beltane was also a time when the Otherworld was seen as particularly close at hand.
Early Gaelic sources from around the 10th century state that the druids of the community would create a need-fire on top of a hill on this day and drive the village's cattle through the fires to purify them and bring luck (Eadar dà theine Bhealltainn in Scottish Gaelic, 'Between two fires of Beltane'). This term is also found in Irish and is used as a turn of phrase to describe a situation which is difficult to escape from. In Scotland, boughs of juniper were sometimes thrown on the fires to add an additional element of purification and blessing to the smoke. People would also pass between the two fires to purify themselves. This was echoed throughout history after Christianization, with lay people instead of Druid priests creating the need-fire. The festival persisted widely up until the 1950s, and in some places the celebration of Beltane continues today.
A revived Beltane Fire Festival has been held every year since 1988 during the night of 30 April on Calton Hill in Edinburgh, Scotland and attended by up to 15,000 people (except in 2003 when local council restrictions forced the organisers to hold a private event elsewhere).