The junction on 6 July of Lieutenant General Rochambeau and his French army with Continental troops outside New York City brightened Gen. George Washington's spirits. He finally could commence operations against the British stronghold. The promise of a powerful French naval squadron under Lieutenant General de Grasse arriving off the American coast increased Washington's optimism and drove him to renew demands on state officials to supply Continental army recruits, militia, and provisions. Failure to comply embarrassed Washington and required awkward explanations to the French allies.

Developments in the southern states offered other opportunities. Major General Lafayette, who commanded in Virginia, shadowed the withdrawal of Lt. Gen. Charles Cornwallis and his British army toward the Chesapeake Bay and deployed his troops to contain the enemy once they took post at Yorktown. Learning that de Grasse would sail to the Chesapeake Bay abruptly changed Washington's thinking. Rather than besiege New York City, he would seize the initiative and move the bulk of his force to Virginia. The allies could shift attention to Charleston if the British escaped Yorktown, but the likelihood was a concentration at the latter location.

The entire French army and part of the Continental army began their march south on 19 August. Already working with astounding energy and stamina, Washington displayed extraordinary physical and intellectual capacity over the next weeks. A feint toward Staten Island, N.Y., baffled Gen. Henry Clinton and kept the British from launching a disruptive flank attack. The logistical complexities of the allied movement can be seen on the map that accompanies the "Narrative Chronology" following Washington's letter to Rochambeau on 17 August.

Washington began the campaign by speaking confidently of how Providence's "common blessing" would lead to an allied victory. Holding strategic and tactical advantages, he could glimpse the ultimate success of the revolutionary cause.