Mills, Warren found the river ford unprotected and established a beachhead south of the river. General Lee convinced his Third Corps commander, A.P. Hill, that Warren's movement was simply a feint, so Hill sent only a single division, commanded by Maj. Gen. Cadmus M. Wilcox, to deal with Warren's supposedly minor threat. The Union troops were taken by surprise and their right flank was beaten back, but they were supported by three batteries of artillery, which slowed the Confederate advance until Union reinforcements arrived to end the brief battle. The next morning, Lee expressed his displeasure at Hill's performance: "General Hill, why did you let those people cross here? Why didn't you throw your whole force on them and drive them back as Jackson would have done?" By the evening of May 23, Lee finally understood that a major battle was developing in this location and began to plan his defensive position. He and his chief engineer devised a solution: a five-mile (8 km) line that formed an inverted "V" shape with its apex on the river at Ox Ford, the only defensible crossing in the area. On the western line of the V, reaching southwest to anchor on Little River, was the corps of A.P. Hill; on the east were Anderson and Ewell, extending through Hanover Junction and ending behind a swamp. Lee's men worked nonstop overnight to complete the fortifications. The new position represented a significant potential threat to Grant. By moving south of the river, Lee hoped that Grant would assume that he was retreating, leaving only a token force to prevent a crossing at Ox Ford. If Grant pursued, then Lee hoped the pointed wedge of the inverted V would split Grant's army and Lee could concentrate on interior lines to defeat one wing; the other Union wing would have to cross the North Anna twice to support the attacked wing. On the morning of May 24, Hancock's II Corps crossed the Chesterfield Bridge with Maj. Gen. John Gibbon's division in the lead. Grant had begun to fall into Lee's trap. Seeing the ease of crossing the river, he assumed the Confederates were retreating. He wired to Washington: "The enemy have fallen back from North Anna. We are in pursuit." The only visible opposition to the Union crossing was at Ox Ford, which Grant interpreted to be a rear guard action, and ordered Burnside's IX Corps