The Lord of the Rings

Dol Guldur ("Hill of Sorcery" in Sindarin), also called "the dungeons of the Necromancer", was a stronghold of Sauron located in the south of Mirkwood.

Dol Guldur was originally known as Amon Lanc ("Bald Hill") in Greenwood the Great. It had been the capital of Oropher's Silvan Elves, who had departed north to the Dark Mountains (later known as the Mountains of Mirkwood). Somewhere after T.A. 1000, an evil presence took over Amon Lanc. It was in 1050 that a shadow fell upon Greenwood and it began to be called Mirkwood. The hostile entity was known as "the Necromancer" by the peoples. Thranduil son of Oropher led his people over the Forest River, where they remained.

Amon Lanc, the "Naked Hill", was a hill in the southern parts of Greenwood the Great. It was capital of the Woodland Realm of the Silvan Elves, for a time, under King Oropher in the Second Age. Around a millennium after his defeat in the War of the Last Alliance, Sauron came to Amon Lanc and claimed Oropher's abandoned stronghold. The hill and fortress were then together called Dol Guldur, and the wood in which it stood became known as Mirkwood. In the Fourth Age, southern Mirkwood became known as East Lórien and, with Dol Guldur cleansed of evil, Amon Lanc was a part of it.

Dol Guldur, also known as the Hill of Dark Sorcery, was Sauron's stronghold and base of operations while secretly regaining his power as "The Necromancer". It was located in the south of Mirkwood and was occupied for most of two thousand years in the Third Age.

The growing shadow in Mirkwood soon attracted the attention of the Wise and Gandalf entered the fortress in TA 2063, seeking to uncover the identify of the Necromancer. Sauron, not yet ready for confrontation, abandoned Dol Guldur and fled into the East, beginning the period known as the Watchful Peace.