The whole story is eminently characteristic of William.  He would be honestly indignant at Guy’s base treatment of Harold, and he would feel it his part as Guy’s overlord to redress the wrong.  But he would also be alive to the advantage of getting his rival into his power on so honourable a pretext.  Simply to establish a claim to gratitude on the part of Harold would be something.  But he might easily do more, and, according to all accounts, he did more.  Harold, we are told, as the Duke’s friend and guest, returns the obligation under which the Duke has laid him by joining him in one or more expeditions against the Bretons.  The man who had just smitten the Bret-Welsh of the island might well be asked to fight, and might well be ready to fight, against the Bret-Welsh of the mainland.  The services of Harold won him high honour; he was admitted into the ranks of Norman knighthood, and engaged to marry one of William’s daughters.  Now, at any time to which we can fix Harold’s visit, all William’s daughters must have been mere children.  Harold, on the other hand, seems to have been a little older than William.  Yet there is nothing unlikely in the engagement, and it is the one point in which all the different versions, contradicting each other on every other point, agree without exception.  Whatever else Harold promises, he promises this, and in some versions he does not promise anything else.

Here then we surely have the kernel of truth round which a mass of fable, varying in different reports, has gathered.  On no other point is there any agreement.  The place is unfixed; half a dozen Norman towns and castles are made the scene of the oath.  The form of the oath is unfixed; in some accounts it is the ordinary oath of homage; in others it is an oath of fearful solemnity, taken on the holiest relics.  In one well-known account, Harold is even made to swear on hidden relics, not knowing on what he is swearing.  Here is matter for much thought.  To hold that one form of oath or promise is more binding than another upsets all true confidence between man and man.  The notion of the specially binding nature of the oath by relies assumes that, in case of breach of the oath, every holy person to whose relies despite has been done will become the personal enemy of the perjurer.  But the last story of all is the most instructive.  William’s formal, and more than formal, religion abhorred a false oath, in himself or in another man.  But, so long as he keeps himself personally clear from the guilt, he does not scruple to put another man under special temptation, and, while believing in the power of the holy relics, he does not scruple to abuse them to a purpose of fraud.  Surely, if Harold did break his oath, the wrath of the saints would fall more justly on William.  Whether the tale be true or false, it equally illustrates the feelings of the time, and assuredly its truth or falsehood concerns the character of William far more than that of Harold.