Gli archeologi e il fiume che non c’è più. Pisa e l’Auser nella prima età imperiale

As ancient authors already highlighted, the history of Pisa is deeply connected to the Auser and Arno rivers. The first one is now disappeared, while the latter has become “the river” of the medieval, modern and contemporary city. Archaeological data show that both rivers played a crucial role in the economic development of Pisa and its ager; it is nevertheless possible to point up that the formation of Pisa as an urban centre was intimately related to the Auser river. Its disappearance in the late Middle Ages created a deep fracture in the layout of the ancient landscape: archaeological evidence related to the centre and the suburbs of Pisa and their connection with the river has become extremely difficult to be fully understood. Trying to reconstruct the urban layout of the city, scholars have often been deceived by the Auser river absence, bringing Pisa back to a “standard” forma urbis. The most recent research – in primis Mappa project – has been able to enhance integrated topographic studies of all the available archaeological evidence, along with an attempt to reconstruct the Auser paths through the comparison of geological and archaeological data. The present essay follows this line of research. We present a reinterpretation of previous studies, focusing on archaeologists’ perception of the relationship between the Auser and the city over time. Moreover, we’ll try to show the Auser river was the centre of gravity of the urban area of Pisa and its suburbs during the Roman Age: given the unstable nature of the ancient landscape, it is not therefore possible, at this stage of research, to present a picture confined into strict spatial and chronological boundaries.