The Battle of Williamsburg, Va., is the first major combat of Union Gen. George B. McClellan’s Virginia “Peninsula Campaign.”

Waged May 4-5, 1862, the battle pitted nearly 41,000 Union soldiers against more than 30,000 Confederate forces. Union forces advancing after a Confederate retreat from Yorktown clashed with a Confederate rearguard near Williamsburg, but were nearly pushed back in attacking Confederates hunkered down behind strong earthworks.

At one point, the Union force appeared close to being repelled before arriving reinforcements shore up their position. The fighting raged on before Confederate forces pulled back at the battle’s end in a nighttime move.

The battle comes as a cautious McClellan, despite tens of thousands of troops, tentatively begins pressing toward Richmond up the peninsula formed by the York and James rivers. More than 3,800 casualties are estimated at Williamsburg, heavily to the Union side.

By May 6, Union forces continue probing toward Richmond, capital of the Confederacy, and a day later there’s a smaller fight of a Union division with two Confederate brigades. But several major battles will lay weeks ahead in McClellan’s ultimately unsuccessful attempt to take Richmond.

The Associated Press reports in a May 11, 1862, dispatch that advancing Union cavalry have pushed on to White House, Va., and the Custis estate owned by a relative of Confederate Gen. Robert E. Lee.

AP reports Virginia’s alarmed “citizens are flocking in from the surrounding country” to the protection of Richmond and Confederates have “burnt the railroad bridge and tore up the road for some distance” toward that city. At the time, AP reports, the closest Union forces are just 23 miles from the gates of Richmond.