The notch at the upper left served to support the lance of a charging knight. The coat of arms is thought to belong to either the von Meissau or the Eglauer family, both of Austria. On the banderoles is the defiant motto IO HARR · LAS UBER GAN (possibly, "Just wait. You'll be beaten"). Part of the motto, IO HARR, is repeated around the border. The shield comes from Reifenstein castle, in the Austrian Tirol. The castle was owned by the religious, military order known as the Teutonic Knights.
Dean, Bashford. Notes on Arms and Armor. New York: The Metropolitan Museum of Art, 1916. illustrated.
Nickel, Helmut. "Arms and Armor From the Permanent Collection." The Metropolitan Museum of Art Bulletin 49, no. 1 (Summer 1991). pp. 20, 64, ill.