Harry Toulmin was a Unitarian minister and politician. The son of noted Dissenting minister Joshua Toulmin, Toulmin fled his native England for the United States after he and his followers were persecuted for their beliefs. He arrived in Virginia in 1793, and aided by recommendations from Thomas Jefferson and James Monroe, he was chosen president of Transylvania Seminary in Lexington, Kentucky. His Unitarian views, however, offended many of the orthodox Presbyterian members of Transylvania's board of regents, and Toulmin resigned after two years.

Joshua Toulmin of Taunton, England was a noted theologian and a serial Dissenting minister of Presbyterian (1761–1764), Baptist (1765–1803), and then Unitarian (1804–1815) congregations. Toulmin's sympathy for both the American (1775–1783) and French (1787–1799) revolutions led the Englishman to be associated with the United States and gained the prolific historian the reputation of a religious radical.