Complex sentence: Afterwards, the company commanders were summoned by the 2nd Battalion commander, Lieutenant Colonel Carlton MacNeely, to Brigadier General Theodore Roosevelt, Jr. 's quarters for a final briefing before the invasion.
Split into simpler sentences: Afterwards, the company commanders were summoned by the 2nd Battalion commander, Lt. Col. Carlton MacNeely, to Brig. Gen. Theodore Roosevelt, Jr. 's quarters for a final briefing before the invasion.