Complex sentence: During the 1862 Peninsula Campaign of the American Civil War (1861--1865), the town was captured from the Confederacy following the Siege and Battle of Yorktown and was then used as a base by the Union Army of the Potomac under General George B. McClellan.
Split into simpler sentences: During the 1862 Peninsula Campaign of the American Civil War (1861--1865), the town was captured from the Confederacy following the Siege and Battle of Yorktown. It was then used as a base by the Union Army of the Potomac under General George B. McClellan.