Henri Matisse, #1913ArmoryShow radical

Art historian William C. Agee calls Matisse “the most radical, most polarizing, most influential artist at the Armory Show — even more so than Duchamp, who was associated with a single work, his famous Nude Descending a Staircase, No. 2. The Cubists caused bewilderment; Matisse caused downright anger.” What was all the fuss about?