"These five rings -- blue, yellow, black, green and red -- represent the five parts of the world now encompassed by Olympism and ready to compete against each other. Moreover, the six colours (including the white background) thus combined represent those of all nations, without exception. The blue and yellow of Sweden, the blue and white of Greece, the French, English, American, German, Belgian, Italian and Hungarian tricolours, the yellow and red of Spain are side by side with the new Brazilian and Australian flags, the old Japan and the new China. It is a true international emblem."
Coubertin (Selected Writings II, p. 460, 1913).