Lugh

Lugh (Old Irish Lug), called Lamfada, of the Long Arm, and Samildanach, skilled in many arts, is one of the foremost gods of the Irish Tuatha De Danann, a youthful, radiant figure of sovereignty, skill and victory. His by-name Samildanach is enacted in a celebrated scene: arriving at the court of Tara, he is refused entry until he can name a craft the household lacks, and when each single skill he offers is found to be already held by someone within, he asks whether they have any one man who possesses them all, and so is admitted, as master of every art at once.

Continental Gaulish inscriptions add a further wrinkle to Lugh's deep antiquity: dedications from what is now Switzerland and Spain address a plural form, the Lugoves, suggesting that on the continent the god behind Lugh's name may sometimes have been venerated as a group of three related deities rather than as a single figure, a pattern of tripling found elsewhere in Celtic religion. Julius Caesar, writing of Gaulish religion in the first century BCE, describes a god he calls Mercury as the most honoured deity among the Gauls, inventor of all the arts, a description many scholars believe points to Lugus behind the Roman name, given how closely it matches Lugh's own later Irish reputation as master of every skill.

In the mythological Cath Maige Tuired (the Second Battle of Mag Tuired) Lugh leads the Tuatha De Danann against the oppressive Fomorians and kills their champion Balor, his own grandfather, whose single destroying eye he puts out with a sling-stone. His name survives across the Celtic world in place-names such as Lugdunum (Lyon), and the harvest festival Lughnasadh, around 1 August, said to have been founded by Lugh in memory of his foster-mother Tailtiu, is one of the four great seasonal feasts of the Irish year and is still marked in modern Ireland. In later tradition Lugh is the otherworldly father of the hero Cu Chulainn, and a related figure, Lleu Llaw Gyffes, appears in the Welsh Mabinogi.

The folklorist Maire MacNeill's landmark 1962 study The Festival of Lughnasa traced a widespread pattern of hill-climbing and harvest gatherings held across Ireland on or near the first Sunday of August, many of them since Christianised, most famously the pilgrimage up Croagh Patrick in County Mayo known as Reek Sunday, and argued convincingly that these customs preserve, in transformed Christian dress, the shape of the pre-Christian Lughnasadh gathering Irish tradition credits to Lugh himself. MacNeill's comparative folklore work remains the standard scholarly reference for tracing Lugh's ancient harvest festival forward into documented living Irish custom.