Após uma simples pesquisa no google, há alguns detalhes no wiki :
Director Peter Jackson first came into contact with The Lord of the Rings when he saw Ralph Bakshi's 1978 animated film The Lord of the Rings. Jackson "enjoyed the film and wanted to know more." Afterwards, he read a tie-in edition of the book[11] during a twelve-hour train journey from Wellington to Auckland when he was seventeen.
In 1995, Jackson was finishing The Frighteners and considered The Lord of the Rings as a new project, wondering "why nobody else seemed to be doing anything about it". With the new developments in computer-generated imagery following Jurassic Park, Jackson set about planning a fantasy film that would be relatively serious and feel real. By October, he and his partner Fran Walsh teamed up with Miramax Films boss Harvey Weinstein to negotiate with Saul Zaentz who had held the rights to the book since the early 1970s, pitching an adaptation of The Hobbit and two films based on The Lord of the Rings. Negotiations then stalled when Universal Studios offered Jackson a remake of King Kong. Weinstein was furious, and further problems arose when it turned out Zaentz did not have distribution rights to The Hobbit; United Artists, which was in the market, did. By April 1996, the rights question was still not resolved.
Jackson decided to move ahead with King Kong before filming The Lord of the Rings, prompting Universal to enter a deal with Miramax to receive foreign earnings from The Lord of the Rings while Miramax received foreign earnings from King Kong. It was also revealed that Jackson originally wanted to finish King Kong before The Lord of the Rings began. But due to location problems, he decided to start with The Lord of the Rings franchise instead.
E aqui está uma postagem em quora :
Peter Jackson won the rights to film J. R. R. Tolkien's epic in 1997 after meeting with producer Saul Zaentz. Originally working with Miramax towards a two-film production, Jackson was later pressured to render the story as a single film, and finally overcame a tight deadline by making a last minute deal with New Line, who were keen on a trilogy.
Jackson first toyed with the idea of filming the apparently unfilmable; a live-action version of Lord Of The Rings. Over the next year, he began to search around for the film rights while making a little-seen 'mockumentary' on the film industry, Forgotten Silver (1996). Ironically, the rights were still owned by Saul Zaentz, the maverick producer who had presided over the another attempt to adapt Tolkien's book for the screen, Ralph Bakshi's 1978 animated version.
A combination of qualities convinced Zaentz, together with producers at both Miramax and New Line, that Jackson alone might be able to deliver the impossible. His obvious talent for fantasy and highly visual filmmaking, his command of cutting-edge special effects, and devotion to Tolkien's work played major parts.