There was a long-standing feud between the two families, and the fact that the Armstrongs were on good terms with their English neighbours, and still more that one of them had married the sister-in-law of a Forster of Yardhope, had greatly embittered the feeling, on his side.

He had long meditated striking a blow at them, and the present time had been exceptionally favourable.
Douglas had his hands full.

He was on ill terms with Rothesay, whose conduct to his daughter had deeply offended him.

The newly-acquired land of the Earl of March gave him much trouble.

He was jealous of the great influence of Albany, at court; and was, moreover, making preparations for a serious raid into England.