At this time the British had subdued Georgia and South Carolina, and Cornwallis was attempting to carry the conquest through North Carolina. In order to keep in touch with his source of supplies the sea, however, he was compelled to fall back to Wilmington. From there, under orders from General Clinton, he marched north to Yorktown, Virginia, where he was joined by a small force of infantry. Washington and Rochambeau had agreed on the necessity of getting the cooperation of the West Indies fleet in an offensive directed either at Clinton in New York or at Cornwallis at Yorktown. Rochambeau preferred the latter alternative, because it involved fewer difficulties, and the message to de Grasse was accompanied by a private memorandum from him to the effect that he preferred the Chesapeake as the scene of operations. Accordingly de Grasse sent the messenger frigate back with word of his intention to go to Chesapeake Bay. He then made skillful arrangements for the transport of all available troops, and set sail with every ship he could muster, steering by the less frequented Old Bahama Channel in order to screen his movement. [Illustration: SCENE OF THE YORKTOWN CAMPAIGN] On August 30 (1781) de Grasse anchored in Lynnhaven Bay, just inside the Chesapeake Capes, with 28 ships of the line. The two British guard frigates were found stupidly at anchor inside the bay; one was taken and the other chased up the York river. De Grasse then landed the troops he had brought with him, and these made a welcome reenforcement to Lafayette, who was then opposing Cornwallis. At the same time Washington was marching south to join Lafayette, and word had been sent to the commander of a small French squadron at Newport to make junction with de Grasse, bringing the siege artillery necessary to the operations before Yorktown. Thus the available farces were converging on Cornwallis in superior strength, and his only route for supplies and reenforcements lay by sea. All depended on whether the British could succeed in forcing the entrance to Chesapeake Bay. Hood, with 14 ships of the line, had followed on the trail of de Grasse, and as it happened looked into Chesapeake Bay just three days before the French admiral arrived. Finding no sign of the French, Hood sailed on to New York and joined Admiral Graves, who being senior, took command of the combined squadrons. As it was an open secret at that time that the allied operations would be directed at Cornwallis, Graves immediately sailed for the Capes, hoping on the way to intercept the Newport squadron which was known to be bound far the same destination. On reaching the Capes, September 5, he found de Grasse guarding the entrance to the bay with 24 ships of the line, the remaining four having been detailed to block the mouths of the James and York rivers. To oppose this force Graves had only 19 ships of the line, but he did not hesitate to offer battle.