Walpole coined the use of the word 'gothic' to refer to a story:

> Gothic fiction began as a sophisticated joke. Horace Walpole first applied the word ‘Gothic’ to a novel in the subtitle – ‘A Gothic Story’ – of The Castle of Otranto, published in 1764. When he used the word it meant something like ‘barbarous’, as well as ‘deriving from the Middle Ages’. Walpole pretended that the story itself was an antique relic, providing a preface in which a translator claims to have discovered the tale, published in Italian in 1529, ‘in the library of an ancient catholic family in the north of England’.
[Source][1].

This was published in the pre-romantic era, when romantic works were seen as gaudy and vulgar by many. By disguising the work as a translation the book was received well (until he revealed his authorship), instead of being rejected like many other romantic works at the time. 
[Source][2]

[More reading][3]

[Development of the romance genre][4]


  [1]: https://www.bl.uk/romantics-and-victorians/articles/the-origins-of-the-gothic
  [2]: https://en.wikipedia.org/wiki/The_Castle_of_Otranto
  [3]: https://en.wikipedia.org/wiki/Gothic_fiction#Horace_Walpole
  [4]: https://en.wikipedia.org/wiki/Romantic_literature_in_English