A calendar of eight festivals falling on the solstices, the equinoxes and four other intermediate dates is observed by many branches of neopaganism. The solstices and equinoxes are widely known as Quarter days; the four dates falling between them are the Cross-quarter days or "fire festivals".
In Wicca the eight festivals are called Sabbats and are distinct from Esbats, which are Wiccan festivals falling at full or new moon. Some modern Druids follow a similar eightfold wheel, but do not refer to the individual festivals as Sabbats. While retaining the Irish names for the fire festivals, they use names derived from the writings of Iolo Morganwg for the solstices and equinoxes. Keltrian druidry uses the same festival names as are common in North American Wicca.
The festivals, with the usual dates of their celebrations, are:
Midwinter/Yule/Alban Arthan, on the winter solstice
Imbolc/Oimelc/Brigid's Day, on February 2 and the preceding eve
Ostara/Lady Day/Alban Eilir, on the spring equinox
Beltane/Beltaine/May Day on May 1 and the preceding eve
Midsummer/Litha/Alban Hefin, on the summer solstice
Lughnasadh/Lammas, on August 1 and the preceding eve
Mabon/Harvest Home/Alban Elfed, on the autumnal equinox
Samhain, on November 1 and the preceding eve October 31
While most of these names derive from historical festivals, the names Litha and Mabon, which have become popular in North America were invented by Aidan Kelly in the 1970s.
This calendar originates in the northern hemisphere, and the symbolism of its festivals follows these seasons. In the southern hemisphere it is common to shift the dates of the festivals by six months to preserve the seasonal symbolism (so that for instance an Australian celebrates Samhain on 1 May, while a Canadian is celebrating Beltane).
Origins of the Wheel
The cross-quarter festivals of Imbolc, Beltaine, Lughnasadh and Samhain were historically observed in medieval Ireland and to a lesser extent medieval Wales; they possibly derive from the first century Gaulish Coligny Calendar which, being a lunisolar calendar, does not correspond to fixed days in the solar calendar; alternatively they may derive from the Roman Kalends, the first of a month.
The four quarter days of the Christian calendar were also observed in medieval and modern Europe and England, on dates close to the solstices and equinoxes, and these are still marked by a variety of folk customs in parts of Europe and the British Isles; for example, traditions involving the Devil collecting nuts at or near the Autumn Equinox are widespread in England; in France it is traditional to leap a bonfire at the feast of St John (24 June).
However there is no place in Europe where all eight festivals have been observed as a set, and the complete eightfold Wheel of the Year is unknown prior to modern Wicca. Its invention is attributed to Gerald Gardner, founder of Wicca, working together with Ross Nichols, founder of the Druidic Order of Bards, Ovates and Druids.
"No known pre-Christian people celebrated all the eight festivals of the calendar adopted by Wicca. Around the four genuine Gaelic quarter days are now ranged the Midwinter and September feasts of the Anglo-Saxons, the Midsummer celebrations so prominent in folklore and (for symmetry) the vernal equinox, which does not seem to have been commemorated by any ancient northern Europeans."
In ancient Iran, Assyria, and Rome, however, the new year began on the vernal equinox. In the case of the Romans, this was 1 March, which became dislodged over time from the astrological Aries/vernal equinox due to Roman calendar drift.
In contrast to the names used in England, in Scotland the fire festivals were (until a change of law in 1991) referred to as Quarter days, also as Term days or Rent days. This has led to some confusion of terminology, as different groups call different sets of festivals the 'Quarter days'.
Modern Interpretations of the Wheel
Some neopagans have adopted dates for the cross-quarter festivals based on a count of days rather than the Calends of the months, working on the assumption that the dates given above derive from the Roman based Gregorian Calendar. They recognize that the fire festivals are near the midpoints between the solstices and equinoxes, and use the midpoint dates instead of the traditional dates. These modern calculations tend to give dates a few days after the traditional calendar based dates - Feb. 4 or 5 for Imbolc, May 6 or 7 for Beltane, Aug. 5 or 6 for Lughnasadh, and Nov. 5 or 6 for Samhain. There is some archeological evidence for such day counting in Neolithic European cultures, including astronomical alignments in tombs to sunrise about a week into November (Samhain).
Other variants of the Wheel sets the four Sun Sabbats (Yule, Ostara, Litha and Mabon) to the solstice/equinox dates, while the other four (called Moon Sabbats) are set depending on the phase of the moon. Some traditions celebrate each of the Cross-quarter days on the closest Full Moon to the modern Gregorian Calendar date associated with each festival. Other traditions celebrate on a chosen mid-season Full Moon (typically the 2nd Full Moon after the preceding Equinox / Solstice, placing the observance 29-59 days into the season with an average of 44 days). Others observe each festival in association with a related mid-season phase of the moon, with Imbolc being associate in various traditions with the New, Crescent, or First Quarter Moon; Beltane with the First Quarter, Gibbous, or Full Moon; Lammas with the Full, Disseminating or Last Quarter Moon; and Samhain with the Last Quarter, Balsamic, or New Moon (See phase of the moon). There are many traditions and opinions, with no definitive interpretation.
Several narratives describe the cycle of the Wheel of the Year. For Neo-Pagans, the most common is the Horned God/Goddes duality. In this narrative, the God is born from the Goddess at Imbolc, courts her maiden aspect at Beltaine, dies at Lammas, passess into the underworld at Samhain, then is born from her mother/crone aspect again at Imbolc. The Goddess, in turn, ages and rejuvinates endlessly with the seasons, being courted by and giving birth to the Horned God.
Another, more solar, narrative is of the Holly King and the Oak King. These two figures battle with each other endlessly. At Midsummer the Oak King is at his height, but the weakened Holly King also begins to regain his strength at that moment. At the Autumnal Equinox, the tables finally turn in the Holly King's favor, and he vanquishes the Oak King at Yule. At this moment, the Oak King begins to regain his footing, and finally manages to turn the tables at the Vernal Equinox
In ancient Greece, the narrative of the wheel is told in the cycle of Persephone, Demeter, and Hades. The year is divided by the pomegranate seeds eaten by Persephone in the underworld, delineating the fertile and infertile cycle of the year.
Astrological signs in the wheel of the year
The eightfold wheel of the year punctuates the path of the sun through the twelve-fold Tropical zodiac. In the northern hemisphere, the sun enters Capricorn at Midwinter, Aries at Spring Equinox, Cancer at Midsummer and Libra at Autumn Equinox. The festivals of Imbolc, Beltane, Lammas and Samhain fall when the sun is approximately halfway through the signs of Aquarius, Taurus, Leo and Scorpio, respectively.