Alpin (dates uncertain, death c.840CE) was the son of the King of the Scots kingdom of Dalriada, Eochaid IV (known as "the Venomous"). His earlier namesake was also the son of an Eochaid (III), but lived about a century earlier. Alpin's mother appears to have been a Pictish princess, possibly named Unuisticc or Fergusia (but not Fergiana).
This Alpin's fame arises from the fact that his son Kenneth I took the kingship of Dalriada, conquered or subdued the other Scottish kingdoms (1) and ruled as king of Scotland or Alba, over Picts, Scots and the Scots Angles, and that he named his house after his father.
(1) Traditionally Scotland was divided into 4 kingdoms, in the north, the Picts; in the east, Bernicia (in the Lothians); in the west, Dal Riada (the Scots who had come over from Ireland); and in the southwest, Strathclyde.