[CLXXVII.] These champions, as well as their wives, took care never to show any signs of fear or alarm even in the time of greatest danger: so Naisi and Deirdre kept playing quietly as if nothing was going on outside, though they heard the din of battle resounding. [CLXXVIII.] The "Three _Tonns_ or Waves of Erin" were the Wave of Tuath outside the mouth of the river Bann, off the coast of Derry; the Wave of Rury in Dundrum Bay, off the county Down; and the Wave of Cleena in Glandore Harbour in the south of Cork. In stormy weather, when the wind blows from certain directions, the sea at those places, as it tumbles over the sandbanks, or among the caves and fissures of the rocks, utters a loud and solemn roar, which in old times was believed to forebode the death of some king. The legends also tell that the shield belonging to a king moaned when the person who wore it in battle--whether the king himself or a member of his family--was in danger of death: the moan was heard all over Ireland; and the "Three Waves of Erin" roared in response. See "Irish Names of Places," Vol. II., Chap. XVI. CHAPTER VI. DEATH OF THE SONS OF USNA. Believing now that they could no longer defend the Red Branch, Naisi took council with his brothers; and what they resolved on was this:--To sally forth with all their men and fight their way to a place of safety. Then making a close, firm fence of shields and spears round Deirdre, they marched out in solid ranks and attacked the hireling battalions and slew three hundred in that onslaught. Concobar, seeing the rout of his men, and being now sure that it was not possible to subdue the sons of Usna in open fight, cast about if he might take them by falsehood and craft. And sending for Caffa, the druid, who loved them, he said:-- "These sons of Usna are brave men, and it is our pleasure to receive them back into our service. Go now unto them, for thou art their loved friend; and say to them that if they lay down their arms and submit to me, I will restore them to favour and give them their places among the Red Branch Knights. And I pledge thee my kingly word and my troth as a true knight, that no harm shall befall them." Caffa, by no means distrusting him, went to the sons of Usna, and told them all the king had said. And they, suspecting neither guile nor treachery, joyfully threw their swords and spears aside, and went towards the king to make submission. But now, while they stood defenceless, the king caused them to be seized and bound. Then, turning aside, he sought for some one to put them to death; but he found no man of the Ultonians willing to do so. Among his followers was a foreigner named Maini of the Rough Hand, whose father and two brothers had fallen in battle by Naisi: and this man undertook to kill the sons of Usna.