When Victor Hugo died in 1885 more than two million people attended his funeral, part of which involved a procession beneath the Arc de Triomphe.

And his legacy has not dimished - Hugo is still regarded as one of the greatest writers in history.

Less well-known is that he was also an artist, largely because Hugo kept his art private.

Why? He wanted to be seen, first and foremost, as a writer, and his paintings might detract from that.

But, more tellingly, he thought it might change the way people saw him.

That worry perhaps makes sense when we see his work.

Far from the heightened realism of Les Misérables - with its memorable characters, deep belief in the human spirit, and profound moralism - Hugo's paintings were experimental, surreal, and almost inexplicable.

Hugo developed a highly distinctive style, drawing primarily on yellow paper with ink, watercolours, and charcoal - he rarely resorted to colour.

The result is a ghostly, vivid style decades ahead of its time, as in La Durande:

It's hard to believe that something like this, titled Marine Terrace, was created by the same person who wrote Les Misérables and The Hunchback of Notre-Dame.

Even the latter, though darker in tone, was nothing quite so bizarre.

Hugo had unusual methods, and would sometimes paint with his left hand without even looking at the page in an attempt to access his subconscious.

He used charcoal, matchsticks, inkwash, and soot to achieve his desired effect.

After the death of his daughter Hugo started attending séances in the hope of communicating with her once again.

And he made drawings while attending them...

His sinister depictions of death, obscure worlds, desolate lands, and mysterious creatures range from chilling to alluring and terrifying to engrossing.

But running through them all is an astonishing individuality. Hence, perhaps, how startlingly modern they feel.

Hugo revealed his Gothic inclinations, previously expressed in The Hunchback of Notre-Dame, with some of these drawings: dark and mysterious castles cast against brooding and dreamlike skies.

Striking about all of them is their atmosphere - one glance pulls us into a world which is familiar but not quite our own, a land of fantastical nightmare.

Then there are his many drawings of hanged men. They have much in common with the sketches of the great Spanish painter Francesco Goya in his later life, despondent and disillusioned with his homeland.

But why did Hugo draw them? Perhaps we'll never know.

Who could have thought that these morbid visions, entirely lacking in any redemptive quality, were produced by the same man who wrote of Jean Valjean?

Justice, from 1858, is one of his most disturbing works.

While the Serpent, from 1866, seems to touch on our most primordial and nightmarish fears, veering into the apocalyptic mysticism of somebody like William Blake.

His use of formless blotches of ink isn't so distant from the revolt of the Impressionists against the French Academy and their realism - only, Hugo did it first.

(Though, that being said, this method is rather reminiscent of traditional Chinese landscape art.)

But it's fair to say that he was ahead of his time.

Hugo's attempts to recreate his dreams on paper and access his subconscious predated Surrealism and abstract art by several decades.

On the left is a portrayal of the sun which would not have been out of place a century after his death.

And on the right? It's untitled. Picasso seems timid in comparison.

But, in the end, Hugo's art defies categorisation.

His was a kind of art totally idiosyncratic, entirely personal and devoid of any obvious influence, both in style and substance.