Complex sentence: Commanding the USS "John Adams" from 1849 to 1853, Barron was made a Captain in September 1855 before serving as Captain aboard the steam frigate USS "Wabash", whose crew included Midshipman George Dewey, from 1858 until 1859.
Split into simpler sentences: Commanding the USS "John Adams" from 1849 to 1853, Barron was made a captain in September 1855. He then was captain of the steam frigate USS "Wabash", whose crew included Midshipman George Dewey, from 1858 until 1859.