After Oromë found the Elves in Cuiviénen, the Valar planned to make War against Melkor. Oromë and Tulkas had dwelt with the Elves for many years, protecting them, so when they left to make war preparations, the Valar sent a group of great Maiar to guard the Elves meanwhile. They were Tarindor (later Saruman), Olórin (Gandalf), Hrávandil (Radagast), Palacendo and Haimenar. They were led by Melian, who had travelled to Cuiviénen before the Five Guardians; she was the sixth Maiar guardian and was the only female spirit among them. It is unrecorded how long the guardians remained at Cuiviénen or if they accompanied the Eldar on the Great Journey.
Other versions of the legendarium
The Five Guardians appear in a late and unfinished version of the legendarium, written by J.R.R. Tolkien while revising key dates of the Valian Years. As the editor Carl F. Hostetter comments, these five Maiar were apparently the later Istari, but the last two names are not specified, so it is unclear if they correspond to the earlier Blue Wizards.