21. However, even evil moments have their end. Sauron's command of Tol Sirion ended eight years after he had captured it. Who were responsible for ousting him from the island, as "The Silmarillion" says?
From Quiz Tolkien Gallery #4: Sauron
Answer:
Luthien Tinuviel and Huan, the Hound of Valinor
Despite the fact that Barahir was slain after Gorlim's betrayal, his son, Beren, had been sent away on an errand by his father, and thus escaped. For four years he wandered in the lands of Dorthonion, a lone outlaw. However, so tight was he pressed by the hosts Sauron and Morgoth sent against him, that he fled the land and crossed the Ered Gorgoroth, that no Man or Elf had dared to cross and ended up in the hidden realm of King Elu Thingol, Doriath. There, he saw and fell in love with the King's daughter, Luthien Tinuviel. The King demanded that Beren bring him a Silmaril from Morgoth's crown in order to take Luthien as his wife.
Beren enlisted the aid of Finrod Felagund, an Elven king who was indebted to his father and, with a small band, they began their Quest. However, Sauron saw them from his tower and captured them. Although Finrod fought him, he lost, and the lot was thrown into a pit in order to be devoured by a werewolf.
At the grim hour where only Beren remained alive, Luthien and Huan, the Hound of Valinor, stood upon the bridge of Tol-in-Gaurhoth. Sauron knew that she was the daughter of Thingol and wanted to turn her over to Morgoth, but neither he nor his lackeys could withstand the Hound of Valinor. Thus, Sauron was forced to flee his island and he went to the forest of Taur-nu-Fuin, filling it with horror.