The detailed study of Eurasian ornamental forms was begun by Alois Riegl in his formalist study "Stilfragen: Grundlegungen zu einer Geschichte der Ornamentik" ("Problems of style: foundations for a history of ornament") of 1893, who in the process developed his influential concept of the "Kunstwollen". Riegl traced formalistic continuity and development in decorative plant forms from Ancient Egyptian art and other ancient Near Eastern civilizations through the classical world to the arabesque of Islamic art. While the concept of the "Kunstwollen" has few followers today, his basic analysis of the development of forms has been confirmed and refined by the wider "corpus" of examples known today. Jessica Rawson has recently extended the analysis to cover Chinese art, which Riegl did not cover, tracing many elements of Chinese decoration back to the same tradition; the shared background helping to make the assimilation of Chinese motifs into Persian art after the Mongol invasion harmonious and productive.