Balor, Lughnasadh, and the Reach of His Name

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.