Few days before the historic ride, Revere was preparing his mission and arranged with three fellow patriots to set up a light signal in case if British troops started their advance to Concord. To give even more information, it was agreed that one lantern meant that the troops chose the longer land route and two lanterns meant the shorter route by water, leaving less time for patriots to react. On the night of April 18, 1775 Dr. Warren dispatched his most trusted messenger to alert patriot leaders in Concord, John Hancock and Samuel Adams that British plan to attack to arrest them and destroy the ammunition supplies prepared to stage armed struggle against the authorities.