Tol-in-Gaurhoth began as the Minas Tirith of Finrod Felagund, and was held by Orodreth for his uncle to guard the vale of Sirion. However, Orodreth was powerless to stop Sauron from taking the isle, and fled south. Sauron began breeding large wolves in the isle which he sent evil spirits in, turning them into werewolves.
Lúthien and the Hound Huan came to Beren's rescue, and while Huan killed the wolves Lúthien got control over the isle's magic from Sauron. The isle was destroyed and cleansed, and remained clean afterwards, and no new tower was erected there.