Summer solstice is the day of maximum light and the beginning of the waning half of the year. This was the day that the sun god, associated with the oak tree and the bull, was defeated by his son who was connected with the lynx and the holly tree. The 2 day solar event coincides with the departure of the Mighty Twins (Gemini) and the arrival of the ship (Cancer) in the zodiac calendar and is in the month of Duir (Oak) in the tree calendar. The two great battles of Magh Tuireadh in Ireland were fought on summer solstice between chieftains who represented the bull and Lynx gods.
Death was considered a precursor to fertility, and the festival which followed honoured female fertility deities such as Artio (Artemis), a moon goddess who was associated with bears, bees and the production of honey. The Manx wore a sprig of Mugwort (Artemisia Vulgaris) on their person during this day. The celebration, which had begun with the sacred fires and sacrifices, was followed by feasting, drinking, dancing and music. During this festival, the youth performed ritual displays to impress the opposite sex. This is the longest day of the year and the heat of sun intensifies.
The Coligny Calendar shows that summer solstice was considered the beginning of the second half or waning half of the year and was in the month of Samonios (June).
July 18 - On this day in 390 B.C. Celtic warriors sacked Rome in revenge for the Roman double-cross during their joint war against the Etruscans. When it came time for the Romans to pay their ransom they accused the Celts of using unjust scales. Ambicatus threw his sword upon the scale and made his legendary statement: "Woe to the defeated."