Ollom Fotla ("the scholar of Fódla", a poetic term for Ireland; later spelled Ollamh Fodhla), son of Fíachu Fínscothach, was, according to medieval Irish legend and historical tradition, a High King of Ireland. His given name was Eochaid.^[1] He took power after killing his predecessor, Faildergdóit, whose father, Muinemón, had killed his father. He ruled for forty years, and died of natural causes at Tara, succeeded by an unbroken sequence of six descendants, beginning with his son Fínnachta, followed by two more sons, Slánoll and Géde Ollgothach.

He is said to have instituted the Feis Temrach or Assembly of Tara. Keating describes the Feis Temrach as an assembly like a parliament, at which the nobles, scholars and military commanders of Ireland gathered on Samhain every three years to pass and renew laws and approve annals and records. The Assembly was preceded and followed by three days of feasting.^[2] He also built a structure at Tara called the Múr nOlloman or Scholar's Rampart.

In the 1870s E.A. Conwell made the claim that Cairn T in the Loughcrew megalithic tomb complex was the tomb of Ollamh Fodhla.^[3][4] The link was based on a claim by James Fergusson ("Rude Stone Monuments in All Countries", 1872, Ch. V, p. 199) that the tomb complex at Loughcrew was the cemetery known as Tailten (or Talten) known from historical documents, with the modern settlement of Teltown being representative of the old place name.^[5] Conwell also linked a large stone with neolithic carvings on it at the site, known as Hag's chair, as the judicial seat of Ollamh Fodhla, who was recorded as being a law giver/maker - this supposed link was a large part of his thesis linking the king and site.^[6] The claim is mostly conjecture.^[3][4]