Clinton knew that the French fleet was expected; but everything pointed to an attack on New York.
If we glance at the map of this section, we shall see that, from his headquarters at West Point, Washington could march half way to Yorktown, by way of New Jersey, without arousing suspicions of his real design.
Nobody but Rochambeau had the least knowledge of what he intended to do. Bodies of troops were moved toward Long Island. Ovens were built as if to bake bread for a large army. The patriots seemed merely to be waiting for the French fleet before beginning in earnest the siege of New York.
Washington wrote a letter to Lafayette which was purposely sent in such a way as to be captured by Clinton. In this letter, the American general said he should be happy if Cornwallis fortified Yorktown or Old Point Comfort, because in that case he would remain under the protection of the British fleet.
Washington wrote similar letters to throw Clinton off his guard. For instance, to one of his generals he wrote in detail just how he had planned to lay siege to New York. He selected a young minister, by the name of Montaigne, to carry the dispatch to Morristown, through what was called the Clove.
"If I go through the Clove," said Montaigne, "the cowboys will capture me."
"Your duty, young man, is to obey," sternly replied Washington.
The hope of the ever-alert commander in chief was fulfilled, for the young clergyman soon found himself a prisoner in the famous Sugar House, in New York. The next day, the dispatch was printed with great show in Rivington's Tory paper.
On August 19, or just five days after receiving the dispatch from De Grasse, Washington crossed the Hudson at King's Ferry, and set out on his long march, with two thousand Continental and four thousand French troops.
They had nearly reached Philadelphia before their real destination was suspected.