“But the last-comer [of the Istari] was named among the Elves Mithrandir, the Grey Pilgrim

“But the last-comer [of the Istari] was named among the Elves Mithrandir, the Grey Pilgrim, for he dwelt in no place, and gathered to himself neither wealth nor followers, but ever went to and fro in the Westlands from Gondor to Angmar, and from Lindon to Lórien, befriending all folk in times of need. Warm and eager was his spirit (and it was enhanced by the ring Narya), for he was the Enemy of Sauron, opposing the fire that devours and wastes with the fire that kindles, and succours in wanhope and distress; but his joy, and his swift wrath, were veiled in garments grey as ash, so that only those that knew him well glimpsed the flame that was within. Merry he could be, and kindly to the young and simple, and yet quick at times to sharp speech and the rebuking of folly; but he was not proud, and sought neither power nor praise, and thus far and wide he was beloved among all those that were not themselves proud. Mostly he journeyed unwearyingly on foot, leaning on a staff; and so he was called among Men of the North Gandalf, ‘the Elf of the Wand’. For they deemed him (though in error, as has been said) to be of Elven-kind, since he would at times work wonders among them, loving especially the beauty of fire; and yet such marvels he wrought mostly for mirth and delight, and desired not that any should hold him in awe or take his counsels out of fear.”

–J.R.R. Tolkien, Unfinished Tales, “The Istari”