The Macdonalds and the Campbells had always been enemies mainly because the Macdonalds were efficient cattle raidera and had stolen even more than cattle from their neighbours.
The Campbell captain was very pleased that technically MacIain had missed the deadline. He was not the only person who hated the wild rebel Macdonalds. The Secretary of State for Scotland, Viscount Stair, was another. His instructions to the captain were to 'put all to the sword under seventy' and to 'be secret and sudden'.
The story is the more terrible because the clanspeople had been guests of the Macdonalds (though some of the soldiers did secretly warn their hosts).