The brother of the architect Octave van Rysselberghe, Théo(phile) began his studies at the Académie van Beeldende Kunsten in his native city. In 1879 he moved to Brussels, where he was taught by the orientalist painter Jean-François Portaels, the director of the Académie Royale des Beaux-Arts. In 1881 Van Rysselberghe took part in the Brussels Salon. The following year, following the example of Portaels, he travelled to Spain and Morocco with Darío Regoyos and Constantin Meunier. Van Rysselberghe returned to Morocco in 1883 and again several times after that.

In 1883 Van Rysselberghe took part in the foundation of the artistic society Les XX, dedicated to the promotion of modern art in Brussels. The presence of artists such as Whistler, Monet and Renoir in the exhibitions of Les XX left an early mark on some of his works, like Portrait of Octave Maus (1885). With the passing of time, Van Rysselberghe became one of the most active members of Les XX, collaborating with Octave Maus in the selection of artists, thanks to his contacts with the Parisian artistic milieux. In 1886, in the company of Émile Verhaeren, Van Rysselberghe contemplated Seurat's painting, Sunday Afternoon on the Island of La Grande Jatte, exhibited at the eighth Impressionist exhibition. A year later Seurat was invited to take part in the Salon de Les XX. Van Rysselberghe himself, without abandoning his vocation as a portraitist, adopted the divisionist technique in 1888. Among his most famous works is Reading (1903, Ghent, Musée des Beaux-Arts), where some of the main French artists and writers of the time are portrayed. Van Rysselberghe also designed furniture and devoted himself to the applied arts, often in collaboration with Henry van de Velde. He also made posters and catalogues for La Libre Esthétique-the successor of Les XX from 1894 onward-and illustrated books by Verhaeren and other poets.

In 1898 Van Rysselberghe moved to Paris, although he maintained close links with the artistic milieu of Brussels, and executed, among other works, a series of decorative panels for the Hôtel Solvay, belonging to Victor Horta (1902). Van Rysselberghe also played an important role in the introduction of the fauvist painters, whom he had met through his friend Paul Signac, to Belgium. From 1903 onward, approximately, his neo-Impressionism began to give way to more restrained forms, and during the last years of his life he also made some sculptures. Van Rysselberghe died on 13 December 1926 in Saint-Clair, France, where he had acquired a house in 1910.

Juan Á. López-Manzanares