To return to the council. The case for the prosecution, as we might term it, was opened by the Bishop of Angers, who charged Stephen both with perjury, that is, with breaking the oath he had sworn to Henry I., and with usurpation in seizing the throne to the detriment of the rightful heir.[762] Stephen's supporters, with Arnulf at their head, met these charges by a defence, the two reports of which are not in absolute harmony. It is quite certain that to the charge of usurpation they retorted that the Empress was the offspring of an unlawful alliance, and had, therefore, suffered no wrong.[763] But how they disposed of the oath is not so clear. According to Gilbert Foliot, whose account we may safely follow, they advanced the subtle and ingenious plea that fidelity had only been sworn to the Empress as heir ("sicut heredi") to the throne, and since (they urged) she was not such heir (for the reason given above), the oath was _ipso facto_ void, and the charge fell to the ground.[764] The other writer asserts that the defence was based, first, on the plea that the oath had been forcibly extorted, and, second, on the cunning pretence that the king had reserved to himself the right of appointing another heir, and had exercised that right on his deathbed, to the extent of disinheriting the Empress and nominating Stephen in her stead.[765] A careful study of the two versions has led me to believe that both writers were, probably, right in their facts. Gilbert Foliot would be the last man to invent an argument in favour of Stephen, nor would the other writer have any inducement to do so, writing (as he did) long after that king's death. Moreover, the pleas that (1) the oath had been extorted, (2) Henry I. had released his barons from its obligation, are precisely those which the author of the _Gesta_ and William of Malmesbury[766] respectively mention as being advanced on Stephen's behalf. Lastly, we have yet another plea advanced by Bishop Roger of Salisbury, namely, that, so far as he was himself concerned, he looked on the re-marriage of the Empress, without the consent of the Great Council, as absolving him from his oath. Now, all this points to one conclusion. The thorn in the side of Stephen and of his friends was, clearly, this unlucky oath. Their various attempts to excuse its breach betray their consciousness of the fact. More especially was this the case before a spiritual court. Hence their ingenious endeavour, described by Gilbert Foliot, to keep the oath in the background as the lesser of the two points. Hence, too, their accumulated pleas. First, they urge that the oath was void because the Empress was not the heir; then, that it was void, because extorted; lastly, that it was void because the dying king had released them from their obligation. Such an argument as this speaks for itself.