Recent earthquakes in Italy, and overseas, revealed building safety shortcomings. People need to know how to prevent such catastrophes. The case of Italy’s heritage buildings is a fine balance between preserving the heritage and making buildings safe to use. In L’Aquila, we renovated some of Italy’s most complex heritage buildings, spanning a wide range of government, civic, and private structures. With nonlinear time history software, we explored and designed systems that preserve heritage’s character, without compromising on robustness. Old decaying buildings are delicate and hard to work with.