The Nazgul, also known as the Ringwraiths and the Black Riders, were once nine mortal kings, until they were corrupted by Sauron and changed into his undead servants. Of all the Dark Lord's minions, the Nazgul were his greatest. They were held in the highest esteem, particularly the Witch-King of Angmar, their captain. When Sauron rose again at the end of the Third Age of Middle-Earth, he dispatched the Nazgul to locate Frodo Baggins and bring the One Ring back to Mordor. They tracked Frodo from the Shire to the ford of Rivendell, where they were washed away and dismounted. When they returned to Mordor, Sauron mounted them on the Fell Beasts (pterodactyl-like creatures) and sent them to lead his armies during the War of the Ring. The Witch-King was slain in the Battle of Pelennor, and the rest of the Nazgul were destroyed when Sauron fell.