1957 Patch, Letterman Army Hospital/Mexico. The Letterman Army Hospital in San Francisco’s Presidio was the site of the Letterman Gym, home of the Letterman Fencing Club. Dr. William O’Brien was the coach there for the duration of their existence. This fully embroidered patch with a motif of foil, sabre and epee surrounding the outline of the US and Mexico is a relic of the 1957 Invasion of Mexico by the Letterman Fencers. Who won and what dark deeds were performed on fencing strips in some gymnasium in the heart of Mexico City the world may never know. Anyway I don’t. This patch is the only record of this event so far uncovered.