Robert Newman, the church sexton at the Old North Church in Boston, hung how many lanterns to warn Paul Revere and the others that the British Regulars were headed to Lexington & Concord (1775)?

two

Revere contacted an unidentified friend (probably Robert Newman, the sexton of Christ Church in Boston's North End) and instructed him to hold two lit lanterns in the tower of Christ Church (now called the Old North Church) as a signal to fellow Sons of Liberty across the Charles River in case Revere was unable to.