Historical building codes issued after the strong Italian earthquakes of Norcia (1859) and Ischia (1883)
Building codes are a fundamental part of the overall strategy for the reduction of seismic risk but their origin is not recent, indeed, sev− eral historical examples are available. After the 1859 Norcia (Central Italy) and 1883 Ischia (Southern Italy) earthquakes two standards were issued, which can be considered a remarkable attempt to improve the performance of ordinary unreinforced masonry structures by regulating architectural configuration and structural details. Both documents contain interesting observations about ground stratigra− phy and topography, masonry units and mortar, vaults and horizontal floors, connections and tie−rods, new and existing construction. All these aspects represent a codification of earthquake−resistant techniques used in seismic zones in accordance with best practice, still extraordinarily relevant when compared with both recent standard recommendations about structural details and with the performance observed during the 2016 and 2017 earthquakes.