Complex sentence: In July 1919, General Lewis commanded the 5th Division and Camp Gordon in Georgia, then the Douglas Arizona District, then the 3rd Division (rock of the Marne) at Camp Pike in Arkansas.
Split into simpler sentences: In July 1919, General Lewis commanded the 5th Division at Camp Gordon in Georgia, then was put in Command of the Douglas Arizona District. He then the 3rd Division (now famously called "The Rock of the Marne") at Camp Pike in Arkansas.