They travel to Rohan, where Gandalf finds that king Théoden has been further weakened by Wormtongue's influence. He breaks Wormtongue's hold over Théoden, and convinces the king to join in the fight against Sauron. Gandalf then sets off to gather Erkenbrand of the Westfold and his warriors to assist Théoden in the coming battle with Saruman. Gandalf arrives just in time to shatter Saruman's attack on Helm's Deep. After the Battle of Helm's Deep, Gandalf and the King ride to Isengard, which in the interim has itself been attacked and conquered by Treebeard and the Ents, along with Merry and Pippin. Gandalf breaks Saruman's staff and expels him from the White Council and the Order of Wizards. Gandalf then assumes Saruman's place as head of both. Wormtongue makes an attempt to kill Gandalf or Saruman with the "palantír" of Orthanc, but misses both. Pippin retrieves the "palantír", but Gandalf quickly takes it, passing it to Aragorn. After the group leaves Isengard, Pippin takes the palantír from a sleeping Gandalf, looks into it, and comes face to face with Sauron himself. Gandalf then takes the chastened Pippin with him to Minas Tirith to keep the young hobbit out of further trouble.