André was part of the invasion of Philadelphia in 1777. At the time, Philadelphia was the largest city in the thirteen colonies. The British captured it. André fought in the Battle of Brandywine, the Paoli Massacre, the Battle of Germantown, the Battle of Monmouth, and Grey's raids into Massachusetts and New Jersey in 1778. André kept a personal book during this time. That book is now a valuable historical source about the war.