Professor (1787–1854) at the University of Pennsylvania, director of the US Mint, and cryptology enthusiast who frequently exchanged coded messages with Thomas Jefferson. Partly-printed DS issued to Patterson, signed by two managers and two physicians of the Pennsylvania Hospital, one page, 19 x 22, May 10, 1809. Document certifying “that Robert Maskell Patterson, Student of Medicine of Philadelphia hath attended the practice of the Physicians of the Hospital for Three Seasons.” The document features a gorgeous engraving of the hospital and retains its paper seal affixed to the lower left. In fine condition, with intersecting folds (small separations at intersections repaired with tape to reverse). RR Auction COA.