We're coming up on the 20th anniversary of the premiere of The Fellowship of the Ring, the first film of the trilogy The Lord of the Rings. It opened only three months after 9/11 and gave us a reason to escape the news and feel joy again... and made us look forward to the later installments. But The Lord of the Rings had been in development for years, and Peter Jackson's production was a massive effort.
Even when the project was greenlighted, casting all those roles presented a problem: any actor who took a role in The Fellowship of the Ring had to commit to an 18-month shooting schedule in New Zealand, and most would also have to commit to appearing in the The Two Towers and The Return of the King, which would all have a similar shooting schedule. Add in the fact that the actor who was cast for the role of Aragorn was fired just before shooting began and you can imagine what the casting director was going through.
Read about eleven actors who wanted a role in The Lord of the Rings and didn't get it, or else were offered a role and decided not to take it, at Mental Floss. Then imagine what a different trilogy it could have been.