{{Infobox Artist
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| name          = Theo van Doesburg
| image         = Theo van Doesburg in military service.JPG
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| location      = Utrecht, Netherlands
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| deathplace    = Davos, Switzerland
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thumb|"Counter-Composition V" (1924)
thumb|A reconstruction of the dance hall/cinema designed by Theo van Doesburg (with [[Hans Arp and Sophie Taeuber-Arp: “Cinébal” in the ''Aubette'' of Strasbourg]]
'''Theo van Doesburg''' (Utrecht, Dutch artist, practicing in painting, writing, poetry and architecture. He is best known as the founder and leader of De Stijl.

==Biography==
===Early life===
Theo van Doesburg was born as '''Christiaan Emil Marie Küpper''' on August 30 1883 in Utrecht as the son of the photographer Wilhelm Küpper and Henrietta Catherina Margadant. Early in his twenties he started using the name of his stepfather Theodorus Doesburg to sign his early paintings. His first exhibition was in 1908. He supported his works by copying paintings from the Rijksmuseum and writing for magazines.

===The De Stijl movement===		
It was while reviewing an exposition for one of these magazines, in J.J.P. Oud they founded the magazine ''De Stijl'' in 1917.

===Promoting De Stijl===
Although 'De Stijl' was made up of many members, Van Doesburg was the 'ambassador' of the movement, promoting it across Europe. He moved to Weimar in 1922, deciding to make an impression on the Bauhaus principal, Walter Gropius, in order to spread the influence of the movement.

While Gropius accepted many of the precepts of contemporary art movements he did not feel that Doesburg should become a Bauhaus master. Doesburg then installed himself near to the Bauhaus buildings and started to attract school students interested in the new ideas of Constructivism. Dadaism, and De Stijl.

===The split with Mondrian===
thumb|"Arithmetic Composition" (1930)

The friendship between Van Doesburg and Mondrian remained strong in these years, although their primary way of communication was by 
letter. In 1923 Van Doesburg moved to Paris together with his wife Nelly van Doesburg. Because the two men got to see each other on a much more regular basis the differences in character became apparent: Mondrian was introvert, while van Doesburg was more flamboyant and extravagant. During 1924 the two men had disagreements, which eventually lead to a (temporary) split in the same year. The exact reason of this split has been a point among art historians; usually the divergent ideas about the directions of the lines in the  paintings have been named as the primary reason: Mondrian never accepted diagonals, whereas Doesburg insisted on the diagonal's dynamic aspects, and indeed featured it in his art. However, Mondrian accepted some concepts of diagonals, such as in his "Lozenge" paintings, where the canvas was rotated 45 degrees, while still maintaining horizontal lines. In recent years, however, this theory gained critique from art historians such as Carel Blotkamp, who cites their different concepts about space and time as the main reason for the split. After the split Van Doesburg launched a new concept for his art: Elementarism, which was characterized by the diagonal lines and rivaled with Mondrian's Neo-Plasticism.

In 1929 the two men became reconciled when they accidentally met in a café in Paris.

===Architecture, design, and typography===
thumb|right|280px|Example of Van Doesburg's ''Letterklankbeelden''
Van Doesburg had other activities apart from painting and promoting De Stijl: he made efforts in architecture, designing houses for artists, together with Georges Vantongerloo and he designed the decoration for the Café Aubette in Strasbourg. Together with El Lissitzky and Kurt Schwitters, Van Doesburg pioneered the efforts to an International of Arts in two congresses held in Düsseldorf and Weimar, in 1922. A geometrically constructed alphabet Van Doesburg designed in 1919 has been revived in digital form as Architype Van Doesburg. This typeface anticipates similar later experimentation by Kurt Schwitters in his typeface Architype Schwitters.

'''Theo van Doesburg''', pseudonimo di '''Christian Emil Marie Képper''' (Utrecht, Olanda, 30 agosto 1883 - Davos, Svizzera, 7 marzo 1931), fu innanzitutto un pittore, poi proseguì la sua carriera come scrittore e studioso delle arti figurative e dell'architettura.

Iniziò la sua carriera come pittore collaborando con gli architetti Jacobus Johannes Pieter Oud e Wils. La sua prima mostra di quadri si tenne all'Aja nel 1908. Sull'esperienza cubista, nel 1915 approfondì la ricerca per elaborare un metodo progettuale esatto e rigoroso. Nei suoi progetti architettonici degli anni intorno al 1920 scompone per poi ricomporre in parte superfici, piani e i fattori essenziali dell'architettura; allo stesso modo in pittura realizza intersezioni di linee e superfici colorate, come in ''Composizione in bianco e nero'', del 1918.  Cercò di raggiungere la tridimensionalità in pittura. Nel 1916 fonda con Piet Mondrian il gruppo Sphinx, nel 1917 il movimento De Stijl che decantava il radicale "rinnovamento dell'arte".

La pittura aveva il compito di valorizzare l'Monaco uno scritto sui principi basilari delle arti plastiche "''Grudbegriffe der neuen Gestaltenden Kunst''".

Nel 1927 realizzò il restauro del Cafè de l'Aubette a Strasburgo insieme a Hans Arp e Sophie Taeuber; in questo intervento è evidente la sua visione spaziale mediante sintesi geometrica e colori puri.

L'anno prima della sua morte progettò di costituire un nuovo gruppo d'avanguardia; tale decisione probabilmente derivava dall'amarezza per l'esperienza negativa dell'incontro con il Bauhaus di Walter Gropius a Weimar.