Ar-Pharazôn, the twenty-fifth King of Númenor, wished to challenge Sauron for the mastery of Middle-earth, so he travelled to Mordor with an army so great it frightened Sauron's servants, who fled. Therefore, Sauron humbled himself before Ar-Pharazôn, and was brought to Númenor as a prisoner. Three years later, he soon used "the cunning of his mind" to become the primary councillor of Ar-Pharazôn and corrupted the minds of most of his people, so that they turned to the worship of the Darkness and Melkor its Lord. Unable for the time being to claim personal divine status anew, Sauron preached deliverance from death and promise of power through an unseen object of worship: his old master, Melkor. After the Númenóreans fully embraced the adoration of the Darkness, Sauron commanded for a mighty Temple to be built on a hill in the middle of Armenelos.
The Temple had a circular foundation and walls that were five-hundred feet high and fifty-feet thick at the base; it was five-hundred feet in diameter. The Temple was roofed by a mighty silver dome which could be seen at a distance due to how it glittered when it was struck by sunlight. However, the dome was soon blackened from the smoke of rituals, as the structure's innermost sanctum contained an altar of fire in its center. There was a louver at the uttermost top of the dome that let out a great smoke regularly. The first sacrifice made on the altar of fire was the chopped-up wood of Nimloth. For seven days afterwards, the city was covered in a cloud before it dispersed and passed away toward the west, though the reek of the burning was admired by many Númenóreans.
Soon afterwards, the King's Men began making human sacrifices upon the altar, hoping that Melkor would release them from the Gift of Ilúvatar, but they did not escape the fate of Men by making these bloody offerings. Many of these sacrifice victims were among the Faithful, though they were never sentenced openly based on their rejection of Morgoth alone. Because of the worship of Morgoth, the skies above Númenor became increasingly engulfed by thunderclouds shaped like Eagles, which often brought death. Sauron laughed when he heard these storms. During one such storm, "a fiery bolt smote the dome of the Temple and shore it asunder", causing it to catch fire. The Temple, however, was itself unaffected, since Sauron stood atop the dome, defying the lightning and remaining unharmed. As a result, the King's Men believed him to be a god and obeyed him without question.
As Ar-Pharazôn's Great Armament departed for war, Sauron remained in the innermost circle of the Temple, laughing at the fleet's trumpets of war before demanding more victims for sacrifices. Sometime afterwards, some soldiers of Sauron went to Rómenna to drag Elendil himself to the Temple; he avoided them before setting sail for Middle-earth.
In S.A. 3319, nine-hundred-and-thirteen days after the Great Armament set sail, "fire burst from the Meneltarma" and even while Sauron laughed at finally having gotten rid of the Edain, the black seat he was sitting in and even the Temple itself were cast "into the abyss" that Eru had made; thus, the Dark Lord's physical form was caught in the ruins, but his spirit survived the catastrophe and later returned to Mordor.