Radagast the Brown, also known as Aiwendil, was one of the Wizards sent to Middle-earth to contest the will of Sauron. Originally a Maia of Yavanna, he had a strong affinity for animals. He dwelt, for a time, at Rhosgobel on the western eaves of Mirkwood, near the Gladden Fields on the Great River.
The Maia Aiwendil was an Ainu who existed before time, and one of the spirits who descended to Arda in order to serve the Valar. Aiwendil was a servant of the Valië Yavanna, the Queen of earth.
After the Undying Lands were separated from Arda during the Downfall of Númenor, Manwë was still concerned for the fate of the peoples of Middle-earth. He summoned a council of the Valar and it was decided that they would send emissaries to Middle-earth. Aulë chose Curumo, Oromë chose Alatar, and Manwë chose Olórin. Yavanna subsequently begged Curumo to take Aiwendil with him.
In c. T.A. 1000, the Maiar arrived upon the shores of Middle-earth, having the form of old Men, whom the peoples called Wizards. Curumo arrived first and alone, and Aiwendil arrived at the same time as Olórin.
Travels in Middle-earth
When the Wizards took their mission they roamed Middle-earth, but Radagast was never much of a traveller. There is not much to be told about his early journeys, but by the late Third Age he eventually settled down and dwelt, for a time at least, at Rhosgobel somewhere between the Carrock and the Old Forest Road. Situated on the western borders of Mirkwood, it can be assumed that the Wizard held watch against the Shadow of Dol Guldur that slowly engulfed the forest. It is likely that he became acquainted with the inhabitants of that region. Close to animals and birds, he was friends with the great eagles. Although the neighboring Beorn was unsociable, he used to see him from time to time, and he considered Radagast 'not bad' for a Wizard.
In T.A. 2851 the White Council met once more and, after that, Saruman began to search the Gladden Fields for the One Ring. Radagast decided to aid his search with birds and beasts who acted as spies hoping that Saruman's actions would help watch and hinder Sauron. Radagast did this in good faith, knowing nothing of Saruman's real ambitions to keep the Ring for himself.
By the time of the War of the Ring Radagast did not dwell any more in Rhosgobel. In summer T.A. 3018 Saruman told Radagast that he was willing to help Gandalf, and sent the Brown Wizard to seek him out at once. Radagast did not know much of Eriador but sought for the Shire, knowing that he would find Gandalf nearby.
Indeed, on Midsummer's Day, Radagast was sitting on the side of the Greenway with his horse near Bree when Gandalf found him on his way to the village. Radagast warned Gandalf that the Nazgûl were abroad, disguised as riders in black, and that they were seeking news of the Shire. He also gave him Saruman's invitation and agreed to help Gandalf by getting beasts and birds to send news to Orthanc. With that he rode away back towards Mirkwood.
By sending Gandalf to Orthanc, Radagast unwittingly had him captured. Saruman's message proved to be a trap for Gandalf who was imprisoned in Orthanc, but still he did not believe that Radagast was also a part of Saruman's plans. Indeed, it was thanks to Radagast that Gandalf was able to escape from the pinnacle of Orthanc upon the wings of Gwaihir.
Radagast's actions during and after the rest of the War are not recorded. After the Council of Elrond, many scouts were sent out from Rivendell to many different locations. Some passed over the Misty Mountains and eventually came to Rhosgobel, but they found that Radagast was not there.
Radagast is, of course, a worthy wizard, a master of shapes and changes of hue; and he has much lore of herbs and beasts, and birds are especially his friends.
Little is known about Radagast apart from certain defining characteristics. Saruman was the chief of the Order of Wizards and Gandalf came next in the order; Radagast meanwhile held much less power and wisdom.
As one of the Maiar of Yavanna, Radagast had a great interest in the kelvar and olvar of Middle-earth and was a friend to beasts and birds. Gandalf, however, held greater respect from, and knowledge about, birds than Radagast.
Radagast displayed some qualities of innocence and naivety, making him an ideal accomplice of Saruman's plans, seen in providing his services to help the White examine the Gladden Fields. Saruman in turn considered him Simple(minded) and a Fool.
In a manuscript written by Tolkien in 1954, the name Radagast is said to mean 'tender of beasts' in Adûnaic, the language of the Númenóreans. However, in a later note Tolkien said that the name is in the language of the Men of the Vales of Anduin, and that its meaning is not interpretable.
As stated by Hammond and Scull, several theories have appeared concerning the inspiration of the name Radagast. One such theory has been proposed by Douglas A. Anderson, who notes the name Redigast in Slavic mythology. John D. Rateliff suggests another source of inspiration in the Gothic chieftain Radagaisus, whose name (as noted by David Salo) is rendered Rhadagast in some works from the 18th and 19th century (e.g., King Alfred's Anglo-Saxon Version of Boethius' De Consolatione Philosophiae, translated by J.S. Cardale in 1829).
The similarity to Old English rudugást meaning 'red-brown spirit' has also been noted by fans.
The name Aiwendil (pron. [aɪˈwendil]) is Quenya for 'lover of birds'. It is obviously derived from aiwe ('(small) bird') and ndil ('devoted to').
Other versions of the Legendarium
From the first drafts of The Hobbit, Bladorthin identifies Radagast as a fellow wizard and as his 'cousin'. John D. Rateliff notes that, at this stage in the development of Tolkien's legendarium there was no reason why a wizard could not have a cousin. Rateliff also suggests that it is likely that Tolkien considered explaining Gandalf's absence (following the departure of Thorin and Company from Beorn's house) by saying that he went to visit Radagast (who lived close by) to plan the attack on the Necromancer.
Early in the process of writing The Lord of the Rings, it is clear that Tolkien envisaged some role for Radagast in the tale. He eventually decided that he would use Radagast as the means of getting Gandalf to Isengard.
Initially Gandalf describes Radagast as his 'cousin', as he did in The Hobbit, but in a subsequent draft he becomes his 'kinsman'. In the final version Gandalf merely says that Radagast is 'one of my order'.
Tolkien initially called him 'Radagast the Grey', but in pencil he changed this to 'Brown' and subsequently Saruman refers to him as 'Radagast the Brown'.
When Tolkien finished writing the story up till Moria, he made notes on the future story development; therein he considered handing over Isengard to Radagast.