"Arise, arise, Riders of Théoden! Fell deeds awake, fire and slaughter! spear shall be shaken, shield be splintered, a sword-day, a red day, ere the sun rises! Ride now, ride now! Ride to Gondor! After blowing the horn, Théoden adds: Ride now, ride now! Ride to Gondor!" - Theoden
The Battle of the Pelennor Fields was a battle for the city of Minas Tirith, and ultimately for Gondor, immediately following a large-scale siege of Minas Tirith by Sauron's army. It was the greatest battle of the War of the Ring, and indeed the largest of the entire Third Age. Major casualties resulted from the battle, including the deaths of King Théoden and the Witch-king of Angmar.
THE WAR (PART I) -
Unknown to both Gondor and Mordor, the Drúedain secretly guided Théoden's army safely through the Drúadan Forest via an old, hidden road built by the Men of Gondor long ago, and forgotten by all save the Wild Men. This allowed the Rohirrim to circumvent the defenses of the enemy on the northern road, and attack the forces of Mordor from the rear. Due to the dismantling of the Rammas Echor, Sauron's forces could not mount a strong defense, and Théoden's forces quickly overran the northern half of the Pelennor Fields. However, after forcing the retreat of the Haradrim cavalry, they were halted by the appearance of the Witch-king. He mortally wounded Théoden, who was crushed by his own horse Snowmane. At that moment, Éowyn and Meriadoc Brandybuck rode up to face him. Éowyn killed the Fellbeast upon which he rode, and the Witch-king fell to the ground. He was unharmed by this, however, and he stood up menacingly, readying his mace. He swung at Éowyn, who managed to block the attack with her shield, which shattered under the great mace's force. Éowyn's arm was also shattered upon impact. She fell to the ground, and the Witch-king lifted his mace for a final blow. As he did so, Merry, who was behind him, stabbed him in the back of the leg with his Barrow-blade. The Witch-king was wounded, and Éowyn used this distraction to drive her sword into his face, killing him. During this, and afterwards, the Rohirrim, under the command of Éomer, continued their assault, while the footmen of Gondor launched their own counterattack, sortieing from the gate while Imrahil, his Swan Knights and Gondor's cavalry tried to reach Éomer. Even so, they were all outmatched by the Mûmakil and Haradrim, as the enemy committed their reserves. As the tide of battle turned against Gondor, the Men of the West were dismayed to see the Corsairs of Umbar had arrived.
THE AFTERMATH -
The Dark Host was lost all but completely. Few ever made it to Mordor, and fewer still survived of the Haradrim forces. However, they only represented a fraction of the forces of the Dark Lord. Most important to Sauron was the loss of his mightiest servant, the Witch-king. Although the numbers lost were not incredibly significant to Sauron, as he could afford to lose many times that of his enemies, the loss of his chief servant was a devastating blow. The losses of the West were significant as well. In addition to the lost commanders, it was said by Éomer later that not 4000 Riders were combat worthy, and the losses in other forces were probably considerable as well. However, despite that, with the newcomers from southern Gondor and more arriving by prior order of Aragorn, even with all the losses of the battle and the 7000 heading for the Morannon, the city was estimated to be better defended than before the battle, discounting the loss of the Great Gate.