In the latter days of the Second Age, nine kings of Men fell under the sway of Sauron, who promised them Rings that would give them great power. The greatest of the Nine was the Witch-king, a ruthless sorcerer who used his Ring to further his own personal ambitions. The Rings, however, were a trick, and corrupted them, drawing them from the living world and turning them into the Nazg?l, the Ringwraiths. The Witch-king became their Captain, and served Sauron until the Dark Lord's defeat in the war against the Last Alliance of Elves and Men.

For more than a thousand years after Sauron's disappearance, the Witch-king and the other Nazg?l disappeared from Middle-earth. When their master returned in disguise at Dol Guldur, however, they resurfaced, and the Witch-king travelled north to found the realm of Angmar and make war against the North-kingdom of Arnor. With an army of orcs, evil Men, and other foul creatures at his command, he corrupted the kingdom of Rhudaur, destroyed Cardolan, and brought down the great Tower at Amon S?l. Finally, his forces besieged Fornost, the capital of Arthedain, and conquered the North-kingdom at last.

His victory was short-lived, however, for an army of Men and Elves, led by E?rnur of Gondor and the Elf-lord Glorfindel, joined the survivors of Arnor and made war on the Fields of Fornost, west of the once-proud city. The armies of Angmar were destroyed, and the Witch-king fled south to Mordor. Angmar fell to ruin, but Glorfindel prophesied that while the Witch-king was defeated, his doom would not come for some time, and not at the hand of man.

Not long after his return to Mordor, the Witch-king and his Nazg?l besieged the Gondorian city of Minas Ithil and captured it. He renamed it Minas Morgul and made it his new stronghold. In the millennium since that time, he has caused no end of trouble for Gondor, including the disappearance and presumed death of E?rnur and repeated attacks on Osgiliath.