Among them was poor harmless Edgar Atheling, who loved Robert well.

Edgar was not important enough to be severe with.

The King afterwards gave him a small pension, which he lived upon and died upon, in peace, among the quiet woods and fields of England.
And Robert--poor, kind, generous, wasteful, heedless Robert, with so many faults, and yet with virtues that might have made a better and a happier man--what was the end of him?
If the King had had the magnanimity to say with a kind air, 'Brother, tell me, before these noblemen, that from this time you will be my faithful follower and friend, and never raise your hand against me or my forces more!' he might have trusted Robert to the death.

But the King was not a magnanimous man.

He sentenced his brother to be confined for life in one of the Royal Castles.