After most of the Garfagnana region surrendered to the House of Este, these new rulers were immediately concerned with strengthening the defences of castles and fortresses, but early interventions did little to change the lay and settlements of the land. Only later was it decided to improve upon the control of the territory by abandoning the many medieval fortifications with obsolete defence systems that were often the refuge of brigands and impossible to properly garrison. Thus a complex system was designed of fortifications of modern design, real fortresses that could accommodate a good number of men, but, above all, medium and large calibre artillery. The military works were conceived and realized between the sixteenth and seventeenth centuries, finally significantly changing, in many cases, the surrounding settlement structure.
