This paper aims to enrich the mosaic heritage of the ancient city of Ostia with a group of unpublished pavements from the sc. Caseggiato delle Taberne Finestrate, in the fourth Region of the city. This complex, built during the reign of Hadrian, was later decorated with a large number of mosaics with geometrical patterns. These mosaics are actually unseen and – until now – unpublished, but it was possible to reconstruct their aspect and their location thanks to an accurate analysis of the archival record kept in the deposits of the Parco Archeologico di Ostia Antica. A digital restoration of the mosaics has been made with the help of precious photographs and some sketches. This paper aims to show how important it is to “dig” in the archives in order to achieve new data, but also to show how the study of the microcosmos of a pavement or a building can help understand the macrocosmos of an entire district or a city.