Fiacha Cennfinnán

Fiacha Cennfinnán appears in the pseudo‑historical regnal sequences preserved in sources such as the Lebor Gabála Érenn and the Annals of the Four Masters. In those chronicles he is presented as a member of the Fir Bolg, son of Starn and grandson of Rudraige. He becomes High King by overthrowing his great‑uncle Seangann, occupies the kingship for a brief, defined period (reported as five years), and is in turn overthrown and slain by Rinnal, son of Genann. The sources situate him in the legendary past and sometimes place him into calculated chronologies (annalistic 'Age of the World' years or modern back‑calculations), but these chronological placements vary between later compilers.

The principal personal detail preserved in the sources is that his byname denotes a birth trait: the glosses record that he had been born with white hair, hence the epithet rendered as 'little white head.' No further contemporary physical description (dress, stature, or other distinctive features) is provided in the cited regnal and annalistic material.

The supplied sources record only political and martial actions typical of regnal narratives: Fiacha seizes the kingship from his predecessor (Seangann), rules for five years, and is subsequently overthrown and killed by his successor (Rinnal). The texts provide no account of supernatural powers, magical abilities, or other extraordinary faculties; he functions as a legendary human ruler within the annalistic and regnal framework.