A radical Unitarian clergyman, scientist, and English republican revolutionary; among the many things for which he is remembered was his discovery of Oxygen.
A noted supporter of the revolution in France and an agitator for populist change in his native country, Priestley was driven out of England by an incendiary royalist mob that burned his home, laboratory, and meeting house to the ground.
His reputation preceding him he made his way to America where his influence was quickly established – Adams was an early congregant and Jefferson became a personal friend. One of the first letters that Jefferson wrote after winning the 1800 presidential election (first term) was to Dr. Priestley.