Letter not found: from Claude-Boniface Collignon, 28 April 1780. Collignon wrote GW on 15 March 1790: “I have had the honor to write you a letter in date April 28th 1780” (see Papers, Presidential Series description begins W. W. Abbot et al., eds. The Papers of George Washington, Presidential Series. 21 vols. Charlottesville, Va., 1987–2020. description ends 5:227–31).