Growing in strength, Sauron attacked Osgiliath, forcing the defenders to leave, destroying the last bridge across the Anduin behind them. Minas Tirith then faced direct land attack from Mordor, combined with naval attack by the Corsairs of Umbar. The hobbits Frodo and Sam travelled through Ithilien, and were captured by Faramir, Boromir's brother, who held them at the hidden cave of Henneth Annûn, but aided them to continue their quest. Aragorn summoned the Dead of Dunharrow to destroy the forces from Umbar, freeing men from the southern provinces of Gondor such as Dol Amroth to come to the aid of Minas Tirith. Gondor, with the Riders of Rohan as cavalry, defeated the army of Mordor in the Battle of the Pelennor Fields. Aragorn led a smaller army to the Black Gate of Mordor to distract Sauron from the hobbits' quest to destroy the One Ring in Mount Doom. The hobbits succeeded, and Sauron was defeated. The war and the Third Age over, Aragorn was crowned King of both Gondor and Arnor, the sister kingdom in the north.