For the strict observance of this convention, the castles of Berwick, Roxburgh, Jedburgh, Edinburgh, and Stirling, were to be made over to Henry, and to receive English garrisons, all expenses being defrayed by the Scottish king; David, and twenty-one of the earls and barons of Scotland, were to remain as hostages until the delivery of the castles; while each of these noblemen was further required to give up his son, or his next heir, as a pledge for the due performance of his part of the treaty after his own release. Three days after the conclusion of the convention of Falaise, William was allowed to leave his Norman prison, and proceed, in the first instance, to England; where he was to remain, in a state of comparative freedom, until the castles already mentioned were delivered over to the officers of the English king.[415] The conduct of Henry upon this occasion has been characterised by his advocates as generous and lenient; whilst it has been stigmatised by his opponents as harsh and illiberal. Neither view appears to be correct. When William, conceiving himself to have been aggrieved, united in a confederacy which, if successful, would have probably confined Henry within the walls of a monastery for the remainder of his life, the Scottish king was fully prepared to profit to the utmost at the expense of his enemy’s weakness; and Henry did no more with the captive of Falaise than William would have done had their positions been reversed. But to maintain, as it has been sometimes asserted, that he might have put his prisoner to death, is to argue with a total disregard of the principles and sentiments of an age in which the death of an independent prince, like William, would have been even more revolting to the feelings of his contemporaries, than the public scourging of Henry in Canterbury Cathedral would be unsuitable to the ideas of the present time. In depriving his captive of his English fiefs, which were justly forfeited, and in extorting liege homage for Scotland, Henry displayed neither mercy nor leniency, simply availing himself, to the utmost, of an opportunity for advancing his own interests at the expense of his unfortunate rival; and his conduct was that of an able and unsparing politician, exacting his own terms from a fallen foe. As such, it must be judged; and, as such, it is far less open to censure, than his repudiation in prosperity of the promises which he made in his adversity to his earliest and most faithful ally. [Sidenote: A. D. 1175.]