Who Were the Istari?
The problem, however, was that not enough Maiar actually showed up to volunteer, fearful of Sauron’s ever-growing power. The first two messengers were Curumo and Morinehtar, Maiar who would eventually take on the names Saruman the White and Alatar in their human forms. The third, Olórin, would become Gandalf the Grey, and after he spoke of his fears of Sauron’s powers, it was decided that two more Maia would join them: Aiwendil, who would become Radagast the Brown, and Rómestámo, who would become Pallando, and together with Alatar, become known as the Blue Wizards.
The Valar set limitations on what the Istari could do in their mission to protect Middle-earth: they could neither match Sauron’s power directly (he himself, after all, was a fallen Maia), nor could they use their powers to, as Sauron attempted to, dominate the peoples of Middle-earth to do their bidding. They were also given a warning from straying from their mission: if they did not work to guide Middle-earth away from Sauron’s plans to rule it, they would slowly diminish in power and lose their memories of their home of Valinor, trapping them as mortal beings.
