Théoden retreats to Helm's Deep. Battle of the Hornburg begins. Ents complete the destruction of Isengard.
"The Battle of the Hornburg" by Alan Lee
Tolkien's method of interlacing is masterful in the events of this day, for if Isengard had not been nearly emptied of its inhabitants, the Ents would not have found it so easy to destroy.
But our author's most stunning achievement today is the creation of a place so real in our imaginations that we, with Gimli, can feel the solidity of its stone beneath our feet: Helm's Deep. Tolkien has described the gorge and the cliffs into which it was built, Helm's Gate, the tower of the Hornburg, the great Deeping Wall, and the causeway in such detail that artists have replicated it easily.
Although Tolkien's account of the Battle of the Hornburg is accomplished in only ten or twelve pages, it is crammed full of vivid descriptions and action. But perhaps the most memorable is a moment of calm. Aragorn stands above Helm's Gates and gives the signal for a parley, which even the orcs respect. And he warns them:
"'No enemy has yet taken the Hornburg. Depart, or not one of you will be spared. Not one will be left alive to take back tidings to the South. You do not know your peril.'
"So great a power and royalty was revealed in Aragorn, as he stood there alone above the ruined gates before the host of his enemies, that many of the wild men paused, and looked back over their shoulders to the valley, and some looked up doubtfully at the sky."
But the orcs had come to slaughter, and slaughter they did, until Gandalf and Erkenbrand arrive to make Aragorn's words prescient.