Richard’s phrase about the conditions of release which Henry had “extorted”[435] from the king of Scots seems to indicate a consciousness that his father had, in forcing upon the caged Lion of Scotland terms of such abject submission, taken a somewhat dishonourable advantage of the lucky combination of accidents—for it was really nothing more—which had placed William at his mercy.[436] But policy, as well as chivalry, had a share in Richard’s agreement with his royal vassal. Ten thousand marks, paid down in a lump and almost immediately, was probably a much larger contribution than could have been obtained from a country so poor as Scotland without some very substantial concession in return. The retention of the castles was quite unnecessary to the security of England; it must inevitably be a source of constant irritation to the Scots, and thus tend to endanger rather than to safeguard the tranquillity of the border; and the restitution of them was the only real sacrifice which the treaty involved. Richard’s charter is most cautiously worded; he renounces nothing except the direct homage of the Scot king’s subvassals and the explicit mention of “Scotland” by name in William’s own act of homage on this occasion. The former would have been extremely difficult to enforce at the moment, and of very little practical value. As to the latter point, the form of words chosen by Richard involved no recognition of the Scottish claim to a partial independence, and no renunciation or abatement of the English claim to the overlordship of all North Britain. It left Richard and his successors quite free to re-assert that claim explicitly at any future time, and to re-assert it as based not on a concession wrung from a helpless prisoner in 1175, but on their acknowledged right to “all” that William’s predecessors “had done and ought to have done” to the predecessors of Richard in virtue of a series of agreements going back from Henry II and Malcolm III to Eadward the Elder and Donald IV; for the English theory on the subject was that those ancient agreements included, or involved, the homage of the Scot kings to the kings of England for the whole realm of Scotland. The Scottish view was, of course, different; but these divergent views were of little practical consequence so long as no necessity arose for expressing them in words or carrying them out in action; no such necessity had yet arisen, and none was destined to arise for another hundred years. A formula capable of this double interpretation was thus the only kind of formula on which the two parties could agree; and the point of immediate importance was that they should agree so that the Scot’s homage should be done and done quickly, not delayed indefinitely or altogether refused at the eleventh hour. It was done at Canterbury on December 5.[437] [Sidenote: _Dec. 5_]