Modern Fantasy

The modern fantasy genre first took root during the 18th century with the increased popularity of fictional travelers' tales, influencing and being influenced by other early forms of speculative fiction along the way, finally unfurling in the 19th century from a literary tapestry of fantastic stories and gaining recognition as a distinct genre (mainly due to the nigh-ubiquitous recession of fantastic elements from "mainstream" fiction) in the late 19th century. However, even "modern" fantasy wasn't like the fantasy literature that we have nowadays, it was something completely different from famous modern books that are widely known like The Lord of The Rings.
What made fantasy literature become the genre that we know today were writers from the 20th century, such as J.R.R. Tolkien (his books are considered to be a milestone for the modern fantasy genre, and they made it become famous).

  (The cover of The Lord of The Rings the book that made Tolkien and fantasy literature in general famous)