Casey Blake ’78 is senior historian for "The Armory Show at 100: Modern Art and Revolution," an exhibition now at the New York Historical Society (NYHS) through Feb. 24, 2014. In highlighting the importance of the original exhibition—and the reason behind mounting a centennial—NYHS notes: “The 1913 Armory Show… in just less than a month … changed the way Americans thought about modern art. It has been called the most important exhibition every held in the United States.” Blake, himself, calls his work on the centennial show, “the opportunity to tell a story about New York during a period of…