Loarn or Loarn mac Eirc was a king of Dalriada who possibly ruled in the 5th century or 400's as king. He was succeeded by Fergus Mór who died in 501. Meaning their must of been an interregnum between the reign of Loarn and Fergus unless he reigned starting in the 480's based on how short lives were back in the 5th century. Some say he lived between 429-468 although this is theory. 