Complex sentence: Before the Battle of the Wilderness the following year (which proved a costly draw for Confederate forces), Union general Gouvenour K. Warren used Ellwood as his headquarters, and it later served as a Union hospital during the drive to Richmond.
Split into simpler sentences: Before the Battle of the Wilderness the following year (which proved a costly draw for Confederate forces), Union general Gouverneur K. Warren used Ellwood as his headquarters. It later served as a Union hospital during the drive to Richmond.