Complex sentence: When the division departed for France, McNair shared quarters aboard ship with the division's assistant chief of staff for operations, George Marshall; during their long ocean voyage, they forged a personal and professional bond which they maintained for the rest of their careers.
Split into simpler sentences: When the division departed for France, McNair shared quarters aboard ship with the division's assistant chief of staff for operations, George Marshall. During their long ocean voyage, they forged a personal and professional bond which they maintained for the rest of their careers.