Daylight plays an essential role in the analysis of ancient houses. Its availability structures and determines the various possible uses (i.e. affordances) of the built space in the course of the day and throughout the year. Daylight thus acquires an object-like character. The aim of this BMBF-funded project is to develop a metric based on digital reconstruction and computer simulation that establishes connections between the available daylight and its possible uses associated with it in ancient houses and workspaces. The data publication comprises developed software including data for its validation and an application example with documentation. It also includes a database with the historic building research documentation of the case studies as well as calculation results and 3D models of the Ostia and Pompeii case studies