Things of Middle-earth
Horn of Helm Hammerhand
Other Names: Helm's horn
[2758-2759 III, the Siege of the Hornburg:]
Helm had a great horn, and soon it was marked that before he sallied forth he would blow a blast upon it that echoed in the Deep; and then so great a fear fell on his enemies that instead of gathering to take him or kill him they fled away down the Coomb.
One night men heard the horn blowing, but Helm did not return. In the morning there came a sun-gleam, the first for long days, and they saw a white figure standing still on the Dike, alone, for none of the Dunlendings dared come near. There stood Helm, dead as a stone, but his knees were unbent. Yet men said that the horn was still heard at times in the Deep and the wraith of Helm would walk among the foes of Rohan and kill men with fear.
The Return of the King, LoTR Appendix A, Annals of the Kings and Rulers: The House of Eorl
[4 March 3019, when the gates are destroyed in the Battle of the Hornburg:]
But even as the gate fell, and the Orcs about it yelled, preparing to charge, a murmur ... grew to a clamour of many voices crying strange news in the dawn. The Orcs upon the Rock, hearing the rumour of dismay, wavered and looked back. And then, sudden and terrible, from the tower above, the sound of the great horn of Helm rang out.
All that heard that sound trembled. Many of the Orcs cast themselves on their faces and covered their ears with their claws. Back from the Deep the echoes came, blast upon blast, as if on every cliff and hill a mighty herald stood. But on the walls men looked up, listening with wonder; for the echoes did not die. Ever the horn-blasts wound on among the hills; nearer now and louder they answered one to another, blowing fierce and free.
'Helm! Helm!' the Riders shouted. 'Helm is arisen and comes back to war. Helm for Théoden King!'
The Two Towers, LoTR Book 3, Ch 7, Helm's Deep
Contributors: Elena Tiriel 15Aug04; added tidbits: ET 20Aug04