Sméagol's friend Déagol found the One Ring in the River Anduin, Sméagol, later known as Gollum, killed Déagol to get it, and was swiftly corrupted by it. Banished, he went to hide in the Misty Mountains. The Wizards discovered Sauron in Dol Guldur, and drove Sauron from Mirkwood; he returned to Mordor, openly declared himself, rebuilt Barad-dûr, and bred armies of specially large Orcs, Uruks.