Simplify the following text for a Grade 8 native English-speaking person.
Original: After the success of The Hobbit , and prior to the publication of The Lord of the Rings , Tolkien 's publisher requested a sequel to The Hobbit , and Tolkien sent them an early draft of The Silmarillion .
Simplified: The Silmarillion is set in Tolkien 's world Middle-earth , and is about its early history before The Hobbit and The Lord of the Rings .