'The only real Cubism is that of Picasso and Juan Gris. Picasso created it and Gris permeated it with his clarity and his exaltation.' Gertrude Stein, 1933

'I try to make concrete that which is abstract . . . Cezanne turns a bottle into a cylinder, but I begin with a cylinder and create an individual of a special type: I make a bottle - a particular bottle - out of a cylinder.' Juan Gris, 1921

'Gris immediately imposed his conception of Cubism on his work. This was rather an explanation of forms than a complication of forms . . . He pursued this line of expression to the end and methodically polished one of the purest facets of Cubism.' Marcel Duchamp, 1950

'Juan Gris always thought an idea through to the end, with an inexorable rigour. Not that he

was a flat rationalist, set on cold logic. This was a Spaniard, with a fanatical, passionate temperament.' Daniel-Henry Kahnweiler, 1929

'I am fed up with laying on colours in a cold and mechanical way and I would like to be able to produce brushwork. In the countryside I see such solid and materially sumptuous tones and such perfect tones, that they carry within themselves a far greater force than all the combinations of the palette.' Juan Gris, 1918

'Out of pale harmonies of colour, lines ascend; prisms thrust themselves up, grow towards us, spring back, hew out steps in spatial infinity; lead upwards and into depth, spread out, multiply, cluster into chords, are energised by rhythm and dance amid the absolute music of space.' Paul Erich Kuppers, 1920

'I don't understand . . . music.' Gris, 1919

(Photograph omitted)