A lost poem is known to have existed recounting Fiachnae's campaigns against the Saxons, and the Irish annals report the siege, or the storming, of Bamburgh in Bernicia in 623–624.
Sábese que existiu un poema, perdido posteriormente, que facía reconto das campañas de Fiachnae contra os saxóns, e os anais Irlandeses relatan a toma ou asedio de Bamburg, en Bernicia, nos anos 623-624.