Attack on Philadelphia
While the English major general John Burgoyne was fighting in the north, Howe loaded his troops aboard approximately 250 ships and sailed up the Chesapeake Bay for Philadelphia, leaving Burgoyne to face potential disaster. Washington didn't exactly expect to keep Howe out of the city. Nonetheless, he couldn't just hand it to him. Thus, he fought with an outnumbered army. The Battle of Brandywine occurred in September 1777 and was followed by the Battle of Germantown, where the British outflanked the entrenched Continental army.
On October 4, 1777, Howe took Philadelphia, the American capital (though government leaders had previously fled). This might have impressed the British, but it didn't do much for the French, who were beginning to take notice of the American victories in other battles.