Old Irish Lughnasadh, also spelled Lughnasa; modern Irish Lúnasa; Modern Scots Gaelic, Lunasdal) or "Lammas" is a Gaelic holiday celebrated on 1 August, during the time of the harvesting. Lugnasadh was one of the four main festivals of the medieval Irish calendar: Imbolc, Beltaine, Lughnasadh and Samhain. Lughnasadh marked the beginning of the harvest season and was therefore a festival of celebrating mother earth and the abundance of nature.
Lughnasadh translates as "Lughs Wedding" and was dedicated to Lugh, a Sun God of Celtic mythology. Lughnasadh festivals lasted from 15 July until 15 August. Aside from three days of religious rituals, the celebrations were a time for contests of strength and skill. In Ireland, during the Middle Ages, important Lughnasa celebrations were held at Taltiu (modern Teltown ) and Carmun (whose exact location is under dispute). Both locations are named for women who appear to be localized manifestations of the earth goddess.
On mainland Europe and in Ireland many people continue to celebrate the holiday with fires and dancing. The Christian church has established the ritual of blessing the fields. In modern Irish and Scottish Gaelic, the names for the month of August are Lúnasa and Lughnasadh respectively.
A festival corresponding to Lughnasadh may have been observed by the Gauls at least up to ca. the 1st century (see Coligny calendar); the same date was later adopted for the meeting of all the representatives of Gaul at the Condate Altar in Gallo-Roman times. Interestingly, during the reign of Augustus Caesar the Roman's instituted a celebration on August 1 to the genius of the emperor in Lyon, a place named for the Celtic god Lugh.
1 August as the national holiday of Switzerland, ancient homeland of the Iron Age Helvetii, with its traditional bonfires might trace to this ancient Celtic tradition.
There is a play by Brian Friel entitled Dancing at Lughnasa which has also been made into a 1998 movie.
In Neopaganism, Lughnasadh is one of the eight sabbats or solar festivals in the Wheel of the Year. It is the first of the three autumn harvest festivals, the other two being Mabon and Samhain. It commemorates the sacrifice and death of the Corn God; in its cycle of death, nurturing the people, and rebirth, the corn is thought of as an aspect of the Sun God. Some Neopagans mark the holiday by baking a figure of the God in bread, and then symbolically sacrificing and eating it.
Neopagans also use the name Lammas, taken from an Anglo-Saxon and Christian holiday occurring at the same time, that is only as closely related to Lughnasadh as any two harvest festivals amongst agrarian peoples. As the name (from the Anglo-Saxon hlafmæsse "loaf-mass", "loaves festival") implies, it is a feast of thanksgiving for bread, symbolizing the first fruits of the harvest. Neopagan celebrations may have elements from either festival.
Lughnasadh is often defined as a cross-quarter day midway between the summer solstice and the autumn equinox, which is half way through Leo (in the northern hemisphere) or Aquarius (in the southern hemisphere). Lughnasadh in the northern hemisphere coincides with Imbolc in the southern hemisphere. As a sabbat it is preceded by Midsummer and followed by Mabon.