I've been reading a bit about writing in the 19th Century and one thing that struck me is how derivative it was. As you know people at that time had major respect (though starting to decline) for the Old Masters and part of your learning was to copy from their work very directly so you could pick up the right techniques. This applied to writing also. For example Oscar Wilde's writing was known by his contemporaries to be heavily influenced by French modernists and certain English forbears--to the point of being accused of plagiarism. For example his book 'Portrait of Dorian Gray is based of a french novel with a similar theme called 'Au Rebours';

"The publication of The Picture of Dorian Gray in 1891 revealed the main influence quite definitely, for, apart from the fact that Wilde's novel
bears many obvious echoes of the most remarkable of French
decadent novels, the A Rebours of J. K. Huysmans, which
Arthur Symons has called " the breviary of the decadence,"
it contains the following passage which, although A Rebours
is not named, is generally understood to refer to that book,
even if the fact were not otherwise obvious
:
—
"His eyes fell on the yellow book that Lord Henry had
sent him. What was it, he wondered. He went towards
the little pearl-coloured octagonal stand, that had always
looked to him like the work of some strange Egyptian bees
that wrought in silver, and taking up the volume, flung himself into an arm-chair, and began to turn over the leaves.
After a few minutes he became absorbed.
" It was the strangest book he had ever read. It seemed
to him that in exquisite raiment, and to the delicate sound
of flutes, the sins of the world were passing in dumb show
before him. Things that he had dimly dreamed of were
suddenly made real to him. Things of which he had never
dreamed were gradually revealed.

This book so revealed Dorian Gray to himself that he became frankly the Due Jean des Esseintes of English literature. There are differences, to be sure, and the sensations
and ideas of Dorian Gray are not elaborated so scientifically as those of des Esseintes, but there is something
more than coincidence in the resemblance of their attitudes
towards life."

However Oscar Wilde copied with a difference. He was called the 'master of paradox', so when he copied he turned things on their heads, he perverted them, he made them funny--its like when artists copy a pose and change the arrangement of limbs so it ends up different--this is perfectly valid.

"In the essays collected in the book called Intentions,
Oscar Wilde has let us into the secret which produced these
works. That secret is an attempt to push Gautier's idea
of art for art's sake, and Whistler's idea of art as Nature's
exemplar, to their logical conclusions. He outdoes his
masters with the obvious intention of going one better."