(Definition of harp on (about sth) from the Cambridge Advanced Learners Dictionary & Thesaurus Â© Cambridge University Press).
Battle of Saratoga. In late September and during the first week of October 1777, Gate's American army was positioned between Burgoyne's army and Albany. On October 7, Burgoyne took the offensive. The troops crashed together south of the town of Saratoga, and Burgoyne's army was broken. In mop-up operations 86 percent of Burgoyne's command was captured.
The Battle of Lexington. April 19, 1775 at Lexington, Massachusetts. In February, the British Parliament declared the colony of Massachusetts to be in open rebellion and authorized British troops to kill the violent rebels. They were ordered to destroy all of the stores that had ammunition, rifles, or other arms.