“Paul Revere’s Ride” is a nice poem, but Longfellow took some liberties with history. (Not just this time; he also wrote “Evangeline”.) Revere was much more than a messenger, he was a leader of the Patriots of Massachussetts.
On the evening of April 18, 1775 Dr. Joseph Warren sent Revere and Dawes to warn Adams and Hancock of their impending arrest, then continue to Concord to warn the colonists there that redcoats were on their way to confiscate arms and military supplies. (Adams and Hancock were not to be arrested, because British General Thomas Gage disregarded the orders he had received to do so. Dr. Warren knew Gage’s orders before Gage did.)
Dawes left Boston immediately via the South Neck. Revere found a man with the keys to Christ Church and directed him to hang two lanterns (“two if by sea”), then went to the waterfront where men were waiting to row him to Charlestown. Once there he went to the man who had already agreed to lend Revere a horse, and began his famous midnight ride.
Neither Revere nor Dawes reached Concord that night. As they were leaving Lexington they encountered Dr. Samuel Prescott returning home after courting his fiance, and Dr. Prescott agreed to ride with Revere and Dawson to Concord. Dr. Prescott escaped the redcoats who captured Revere, and was the only one of the three to accomplish the mission to warn Concord. (Dawson also escaped but his horse threw him and ran away, leaving him on foot and unable to continue.)