Yeah, Tolkien had no intention to ever create The Lord of the Rings. It was only after The Hobbit's critical and financial success, that his publishers pressured him into writing a sequel. They wanted it to be another children's story regarding Bilbo. Tolkien decided to make it darker and more mature, for adults, starting Bilbo's nephew instead. The Hobbit was published in 1937, and he worked on The Lord of the Rings from 1937-1949.
Tolkien went back and added more back story to events from The Hobbit, for The Lord of the Rings. So this is why Gollum's invisibility ring became the One Ring, etc.
Don't forget it was also a super convenient way to push his made up language. Tolkien was a linguist.
Definitely. You could argue that Tolkien created The Silmarillion just to give a history to the many languages he created. The Lord of the Rings was just a freak accident that occured and turned out to become one of the most popular book/fictional series in history.
Which is honestly fascinating. It's really the grandfather of modern fantasy and it's influence runs incredibly deep.
Which is why even though I don't really enjoy it I respect it for what it is. My two favorite series (Dark Tower & The Second Apocalypse) draw heavily from it's influence. ---