Overview
Ildulb mac Causantín, anglicised as Indulf or Indulph, nicknamed An Ionsaighthigh, "the Aggressor" (died 962) was king of Alba from 954 to 962. He was the son of Constantine II; his mother may have been a daughter of Earl Eadulf I of Bernicia, who was an exile in Scotland.
Biography
Indulf was probably baptised in 927. According to William of Malmesbury, Æthelstan stood godfather to a son of Constantine at the Church of Dacre. The Anglo-Saxon Chronicle dates the meeting of Æthelstan with the northern kings at Eamont to the 12 July 927. So, it is likely that this baptism occurred on, or around, the Feast of St Hildulf, which Alex Woolf suggests may be the source of his uncommon name.
John of Fordun and others supposed that Indulf had been king of Strathclyde in the reign of his predecessor, based on their understanding that the kingdom of Strathclyde had become a part of the kingdom of Alba in the 940s. This, however, is no longer accepted.
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