Fénius Farsaid (also Phoeniusa, Phenius, Féinius; Farsa, Farsaidh, many variant spellings) is a legendary king of Scythia who appears in different versions of Irish mythology.
Nél, who was trained in many languages, married Scota, daughter of Pharaoh Cingris of Egypt, producing their son Goidel Glas.
Finding that the speakers had already dispersed, Fenius sent his scholars to study them, staying at the tower, coordinating the effort.
After ten years, the investigations were complete, and Fenius created in Bérla tóbaide "the selected language", taking the best of each of the confused tongues, which he called Goídelc, Goidelic, after Goídel mac Ethéoir.
He also created extensions, called Bérla Féne, after himself, Íarmberla, after Íar mac Nema, and others, and the Beithe-luis-nuin (the Ogham) as a perfected writing system for his languages, Béarla na bhFileadh - 'language of the poets'.