Parole was a logistics and manpower tool

The discussion treats officer parole as a calculated wartime institution rather than evidence that earlier wars were gentle. Keeping prisoners required food, guards, and transport that might otherwise sustain the field army. Reciprocal release could return a state's own personnel, while paroled officers could be sent to imperial stations where their promise not to fight the captor did not prevent useful service. Taking a city intact after its defenders marched out also preserved the victor's army and the infrastructure it wanted to control. In the world wars, larger food surpluses and administrative capacity made long-term prisoner camps less damaging to front-line sustainment, so states relied less on parole. The practice changed with logistics and state capacity, not with a simple decline from gentlemanly warfare.