As the Istari were Maiar, each one served a Vala in some way. Saruman was the servant and helper of Aulë, and so learned much in the art of craftsmanship, mechanics, and metal-working, as was seen in the later Third Age. Gandalf was the servant of Manwë or Varda, but was a lover of the Gardens of Lórien, and so knew much of the hopes and dreams of Men and Elves. Radagast, servant of Yavanna, loved the things of nature, both animals and plants. As each of these Istari learned from their Vala, so they acted in Middle-earth.