In the beginning of the third age, Saruman the White, chief of all the wizards and two blue Istari, Pallando and Alatar ventured from Angrenost, Gondor’s Fortress (Where the three wizards had been invited to stay at the fortification with the company of Aglarond) to the eastern edges of mirkwood, where the forest met the river Celduin. Here, once the three Istari had set up camp, the white wizard murdered the blue Pallando while Alatar was out collecting wood. Alatar, brother of Pallando sensed his death and ran into the depths of the forest, never to be seen again until he was invited to join the Council of Neunamar when he was walking through the city. Saruman, meanwhile, travelled to the sea of Rhûn where he there allied with the Easterlings and studied darkness and the one ring.
The subject of this article originates from non-canonical sources. To find out about what is considered "canon" see LOTR:Canon.