Nathaniel Chapman (1780-1853), originally from Virginia, received his medical degree from the University of Pennsylvania in 1801 with a dissertation on rabies. Following additional medical training in London and Edinburgh between 1802 and 1803, Chapman received a letter of introduction from his mentor, Benjamin Rush, and met TJ in January 1804. Chapman later sent TJ the prospectus for his own edited volume of British political speeches and corresponded with him on the causes behind “changes of climate.” Chapman opened a private practice in Philadelphia, taught medicine at the University of Pennsylvania between 1810 and 1850, and was a member of the American Philosophical Society. The American Medical Association elected him as the society’s first president in 1848 (ANB description begins John A. Garraty and Mark C. Carnes, eds., American National Biography, New York and Oxford, 1999, 24 vols. description ends ; Nathaniel Chapman, Select Speeches, Forensick & Parliamentary, with Prefatory Remarks, 2 vols. [Philadelphia, 1808]; RS description begins J. Jefferson Looney and others, eds., The Papers of Thomas Jefferson: Retirement Series, Princeton, 2004- , 13 vols. description ends , 1:663; Vol. 42:102-3; Chapman to TJ, 13 Jan. 1807).

After establishing formal U.S. possession of Louisiana, General James Wilkinson (wilkenson) left New Orleans in April and arrived in New York City in late May. After a brief stay, he traveled to Philadelphia and then on to Washington (Alexandria Advertiser, 11 May; New York Daily Advertiser, 21 May, 2 June; Alexandria Expositor, 16 June).

Chapman presumably met the author, Henry Peter Brougham, during his medical studies in Scotland (Robert Stewart, Henry Brougham, 1778-1868: His Public Career [London, 1985], 14-27).