Restoration and maintenance issues for the early modern fortified heritage

War requirements have always modelled regions and cities, strongly conditioning the urban and landscape design with defensive and surveillance works in continuous evolution and reinforcement, up to and after the permanence of conditions of real or potential danger. In the case of fortresses of the modern era, we are often faced with extremely imposing constructions, calculated in terms of size, shape and volume of wall masses, factors necessary to respond to new war requirements due to the technological progress of offensive weapons. These factories represent, from the 16th century onwards, a settlement phenomenon of enormous impact, with foundation, on existing or new buildings, of extremely clear and articulated layout, indebted to the models and solutions of the walled city of the Renaissance, as a perfect interaction between residential and defensive needs. A conscious restoration project cannot abstain from knowledge of these issues if it wants, as it must, to understand the nature, the role of these monuments and their relationship with the city, in the multiple aspects they have taken on over the centuries.