The Time Frame In The Book Is Extremely Long
We're talking about hundreds and thousands of years. It would be interesting to know if Middle-Earth had the same 12 months per year as we do. Everyone, even the humans, lived longer than a 100 years. Example:
The events between the Hobbit and LOTR was 60 years.
Sauron forged the Master Ring over 3000 years before the LOTR took place.
Gollum lived in the underground caves of the Misty Mountains for 500 years.
The Ring laid at the bottom of the River Anduin for 3000 years before being discovered.
After Bilbo had his 111st birthday, he retires from the Shire and the LOTR events don't start moving until 17 years afterwards.
After Gandalf spills out the news of the dangers of the ring to Frodo, they relax and enjoy the peacefulness of the Shire for a couple of months afterwards.
The Ents in Fanghorn forest were extremely ancient. Even the whole forest itself.
That's longevity! In our time, it would be like battling an ancient enemy since the time of the pyramids. Way to go!
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Come to Middle-Earth, a world beyond the furthest reaches of your imagination