Front cover: Au Velodrome - Jean Metzinger 1912

While Picasso and Georges Braque are generally acknowledged as the founders of Cubism, it was Jean Metzinger, together with Albert Gleizes, that created the first major treatise on the new art-form, Du "Cubisme", in preparation for the Salon de la Section d'Or held in October 1912. Du "Cubisme", published the same year by Eugène Figuière in Paris, represented the first theoretical interpretation, elucidation and justification of Cubism, and was endorsed by both Picasso and Braque. Du "Cubisme", which preceded Apollinaire's well known essays, Les Peintres Cubistes (published 1913), emphasized the Platonic belief that the mind is the birthplace of the idea: "to discern a form is to verify a pre-existing idea", and that "The only error possible in art is imitation"

Du "Cubisme" quickly gained popularity running through fifteen editions the same year and translated into several European languages including Russian and English (the following year).

In 1912 Metzinger was the leading figure in the first exhibition of Cubism in Spain at Galeries Dalmau, Barcelona, with Albert Gleizes, Marcel Duchamp, Henri Le Fauconnier, Juan Gris, Marie Laurencin, and August Agero.

In 1913, Apollinaire wrote in Les Peintres Cubistes:

In drawing, in composition, in the judiciousness of contrasted forms, Metzinger's works have a style which sets them apart from, and perhaps even above most of the works of his contemporaries... It was then that Metzinger, joining Picasso and Braque, founded the Cubist City... There is nothing unrealized in the art of Metzinger, nothing which is not the fruit of a rigorous logic. A painting by Metzinger always contains its own explanation ... it is certainly the result of great hindmindedness and is something unique it seems to me, in the history of art.

The new structures he is composing are stripped of everything that was known before him... Each of his paintings contains a judgment of the universe, and his work is like the sky at night: when, cleared of the clouds, it trembles with lovely lights. There is nothing unrealized in Metzinger's works: poetry ennobles their slightest details.