Amazon's original pitch for the television rights to
J.R.R. Tolkien's 'The Hobbit' and 'The Lord of the Rings' novels was to make the series a new adaptation of the latter (effectively a retelling of
El señor de los anillos: La comunidad del anillo (2001),
El señor de los anillos: Las dos torres (2002) and
El señor de los anillos: El retorno del rey (2003)), but the Tolkien estate rejected this proposal. Amazon finally obtained the rights under the conditions that the series be distinct from
Peter Jackson's earlier adaptations, and that they couldn't contradict anything that Tolkien had previously written. Early ideas that were proposed included prequel stories featuring characters such as Aragorn, Gimli and Gandalf, but the showrunners preferred to focus on important untold events from the novels' lore rather than simple side stories, so they settled with the studio that the series would take place during the books' Second Age. Since they didn't have the rights to Tolkien's 'The Silmarillion', 'Unfinished Tales' and 'The History of Middle-earth' (which explore the First and Second Ages), they checked the Lord of the Rings novels and appendices for passages about and references to the Second Age that they could set their story in. They consulted with the estate and several Tolkien lore experts (including grandson and novelist
Simon Tolkien) about the inclusion of new characters and plot elements.