Complex sentence: Expeditionary Forces were in part the antecedent of the modern concept of Rapid Deployment Forces, however traditionally Expeditionary Forces were essentially self sustaining with an organic logistics capability and with a full array of supporting arms.
Split into simpler sentences: Expeditionary Forces were in part the antecedent of the modern concept of Rapid Deployment Forces. Traditionally Expeditionary Forces were essentially self-sustaining with an organic logistics capability and with a full array of supporting arms.