I once lived in Belgium by mistake. I moved into a flat in Ixelles, a district of central Brussels, and spent my free time in museums, where I encountered art by remarkable artists of whom I had never heard. Among these artists were two who are receiving current attention: Fernand Khnopff and Léon Spilliaert.

Symbolism is a late manifestation of Romanticism, the movement dedicated to the irrational, mystical and emotional in art. Symbolism (which flourished from 1840-1914) was an approach which allowed artists to deal with fundamental fears, desires and the meaning of human life through use of general symbols to induce strong emotions in the audience. Both Symbolism and Romanticism were founded on morbidity — a hyperawareness of death and the brevity of life — and a sense of loss at a receding past of heroism.

The greatest Symbolists came from Northern Europe (and Switzerland), as if a hostile climate and long cold nights nurture a melancholy attachment to a fantastic past. The Belgian idealists’ embrace of Symbolism parallels the British embrace of Pre-Raphaelite mythological scenes as a conscious rejection of industrialisation and urbanisation.

The link between Romanticism and Symbolism is Antoine Wiertz (1806-1865). When the Belgian state was formed in 1830, it was in search of an artistic identity, not least to fuse the culturally incompatible Flemish north and French south. Wiertz seemed a sophisticated painter of mythological and modern scenes. He was provided by the state with a house-studio in central Brussels, where he painted giant canvases of mythological tableaux. Today, this house is in the incongruous shadow of the EU Parliament. His best paintings are powerful, macabre and memorable, though too often Wiertz falls short of that, lapsing into banality and bathos.

Brussels became an important industrial, commercial and cultural centre. It was a place of exiles, home to the painter David and poet Baudelaire, frequented by Dutch and French writers and artists. Latterly, it became capital of a colonial regime legendary in its inhumane treatment of Congolese. At the highest point in the city, a gargantuan neoclassical Palais de Justice was built, suitably demonstrating Leopold II’s imperial ambitions. Brussels was one of the hubs of Art Nouveau. Sinuous decoration and elongated proportions dominated houses built in the residential districts, designed by Victor Horta (whose own beguiling house can be visited today).

Symbolism has a paradoxical moral duality at its heart. In one respect, it is a natural home for those who yearn for a gallant pre-industrial feudal society, a world cleansed of the dubious ambiguities of democracy and consumerism; it is also associated with decadence and defiance of moral standards, the pursuit of pleasure and delight in the macabre, grotesque and erotic. Within the movement one finds Jean Delville (ethereal aesthete) and Félicien Rops (worldly libertine) rubbing shoulders, alongside those whose artistic output encompasses myriad (seemingly contradictory) tendencies.

The presiding leader of Belgian literary Symbolism was the Francophone writer Georges Rodenbach, author of two great short novels Bruges-la-Morte (1892) and The Bells of Bruges (1897). Rodenbach found in Bruges — a formerly prosperous port which became frozen in a melancholy stasis when its access to navigable waterways silted up — the epitome of a noble past in a perpetual state of decay. Bruges was “an illuminated reliquary” and “a dead woman around whose tomb a few friends gather”. These novels, full of evocative images and plangent atmosphere, are available in highly readable English translations.

The first illustrator of Bruges-la-Morte was Fernand Khnopff (1858-1921). A new catalogue (Mercatorfonds/Yale, $60) documents his art. Khnopff was a widely-known and influential figure in the international Symbolist movement of the 1890-1914 period. He grew up in Bruges and studied law at university in Brussels before undergoing extensive training in fine art. His art is poetic rather than intellectual in character. Khnopff’s preferred landscapes were rather bucolic views around a forest close to Brussels. The townscapes — typified by An Abandoned City (1904), which shows a few Flemish townhouses being encroached upon by the sea — are the best of Khnopff’s views.

Spilliaert’s motifs of fishermen’s wives standing at the quayside are graphically and emotionally concise

Khnopff built a house-studio in Brussels between 1900 and 1902. It was designed as an immersive spectacle, in the modern style. The building featured high ceilings, dramatic drapes and clean lines, with much painted white. There were satin curtains rather than internal doors. It was designed in a Secession style, with polished walls that give the interior a chilly, unearthly atmosphere. The press described the building as a coded self-portrait: imposing, inscrutable, elegant and individual. Regrettably, this experience is unrecoverable. The art was dispersed by auction after the artist’s death in 1922; the house was demolished in 1938.

What are the other qualities of Khnopff’s art? Timelessness, stasis, immobility, lack of vitality. His nudes are idealistic and detached. They are erotic but sexless, eschewing the sordid and corporeal qualities of the female body. This is the art of a man who venerates women greatly but probably does not understand them much. His only attempt at marriage was late, unsatisfactory and soon dissolved. His sister Marguerite served as his model for clothed figures and mythological characters.

Among subsequent artists were James Ensor, Constant Permeke, René Magritte and Paul Delvaux. Léon Spilliaert (1881-1946), one of the last Belgian Symbolists, was the subject of a recent exhibition (Royal Academy, London, currently closed. A substitute for visiting is the hardback catalogue, £25.) Spilliaert spent most of his life in Ostend. As a young man, he was afflicted by a stomach complaint which led to insomnia. During his nocturnal wanderings, he observed the coastal city at night, deserted and dark. His best pictures are views of Ostend at night, streetlamps reflecting on wet paving stones.

His motifs of fishermen’s wives standing at the quayside, facing out to sea, are graphically and emotionally concise. We get their sense of loneliness and uncertainty. It is a direct observation, honestly felt and crisply executed — a model that young artists would do well to emulate. There are dramatically atmospheric views of the Ostend beach, pavilion and dim streets. A view of the sea from the tower of Mariakerke shows a curving horizon, the watery vastness of the North Sea swelling towards heavy cloud.

There is an air of adolescence about Spilliaert’s approach to art — in his aversion to oil paint, the occasional modishness, the self-absorption, the moodiness. However, he produced some superb pictures. The self-portraits of 1907-8 are set at night and are full of mystery and loneliness. Spilliaert is a poseur, but he is also genuinely troubled and indubitably a great talent. He poses as a damned aristocrat from a Poe tale, a frail scholar, even a wraith. His receding hairline and pronounced bone structure make his countenance strikingly skull-like. These are some of the great self-portraits of the last century.

The catalogue illustrations omit his oil paintings, late works, tree paintings, caricatures and most highly coloured work, all of which are rather weak. The best of Spilliaert’s art sets one dreaming, and we can imagine wandering the night streets with a mysterious companion. Although the current exhibition is unavailable, the catalogue invites us to enter the haunting recesses of Symbolism.