Complex sentence: Little is known of Peter Van Hoesen's early life, but he enlisted with the army during the American Civil War and deserted from Company B of the 18th New York Infantry before the Battle of Crampton's Gap on September 14,1862.
Split into simpler sentences: Little is known of Peter Van Hoesen's life before the American Civil War. He enlisted with the army early in the conflict and deserted from Company B of the 18th New York Infantry before the Battle of Crampton's Gap on September 14,1862.