During the Spanish Civil War, it was a stronghold of the pro-Franco forces, who held out during a 72-day siege that all but destroyed it.
The Fortress was a stronghold of pro-Franco forces.
mnli hypothesis: The Fortress was a stronghold of pro-Franco forces. premise: During the Spanish Civil War, it was a stronghold of the pro-Franco forces, who held out during a 72-day siege that all but destroyed it.