At war with Picts, killed 778 (Williamson, David. Debrett's kings and queens of Britain. Topsfield, Mass. : Salem House Publishers, 1986, pg. 228).
Áed Find (Áed the White) or Áed mac Echdach (before 736?778) was king of Dál Riata (modern western Scotland and County Antrim, Ireland). Áed was the son of Eochaid mac Echdach, a descendant of Domnall Brecc in the main line of Cenél nGabráin kings.
According to later genealogies, Áed was the great-grandfather of Kenneth MacAlpin (Cináed mac Ailpín) who is traditionally counted as the first king of Scots. This descent ran through Áed's son Eochaid mac Áeda Find and Eochaid's son Alpín mac Echdach. The evidence for the existence of Eochaid and Alpín is late and uncompelling, and shows signs of fabrication in the High Middle Ages.
The Annals of Ulster in 768 report "Bellum i Fortrinn iter Aedh & Cinaedh": a battle in Fortriu between Áed and Cináed. This is usually read as meaning Áed Find and the Pictish king Ciniod I, who is called "Cinadhon" in the notice of his death in 775. The Annals of the Four Masters, a less reliable source, give a different version, placing this battle in Leinster and naming the victor as Cináed mac Flainn of the Uí Failgi and his defeated enemy as one Áed.
Áed's death in 778 is noted by the Annals of Ulster. He appears to have been followed as king by his brother Fergus mac Echdach.
The "Laws of Áed Eochaid's son" are mentioned by the Chronicle of the Kings of Alba in the reign of Áed's supposed great-grandson Donald MacAlpin (Domnall mac Ailpín): "In his time the Gaels with their king made the rights and laws of the kingdom [that are called the laws] of Áed Eochaid's son, in Forteviot." What these laws concerned is not known (wikipedia)