William Dawes, Evanston History Center, Evanston, IL. Late on the night of April 18, 1775, Boston patriot Joseph Warren learned of a British military operation planned for the next day.

April 18: At 10pm on a Tuesday night, Dr. Joseph Warren sends Paul Revere and William Dawes, Jr. to Lexington to warn Samuel Adams and John Hancock that the British are planning to march there to ...