§ Of the Rings of Power and the Third Age The Silmarillion

Ever most vigilant was Mithrandir, and he it was that most doubted the darkness in Mirkwood, for though many deemed that it was wrought by the Ringwraiths, he feared that it was indeed the first shadow of Sauron returning; and he went to Dol Guldur, and the Sorcerer fled from him, and there was a watchful peace for a long while. But at length the Shadow returned and its power increased; and in that time was first made the Council of the Wise that is called the White Council, and therein were Elrond and Galadriel and Círdan, and other lords of the Eldar, and with them were Mithrandir and Curunír. And Curunír (that was Saruman the White) was chosen to be their chief, for he had most studied the devices of Sauron of old. Galadriel indeed had wished that Mithrandir should be the Lead of the Council, and Saruman begrudged them that, for his pride and desire of mastery was grown great; but Mithrandir refused the office, since he would have no ties and no allegiance, save to those who sent him, and he would abide in no place nor be subject to any summons. But Saruman now began to study the lore of the Rings of Power, their making and their history.