Medieval archeology in Casentino and the study of fortifications, the Guidi’s in particular, in this territorial context are closely linked to the figure of Guido Vannini. Since he published interventions in the second half of the 1980s, which immediately defined research perspectives, then implemented in the years to come with projects, partly still in progress, among which is also included my thesis work retraced and summarized by the article and centered on a cataloging of the Casentino castles of the Guidi family, contextualized in a broader investigation of territorial archeology on historical issues such as roads, population, fortifications, including non-Guidian ones, in continuous comparison with written sources, as in the case of the section dedicated to the Guidi counts in Casentino, and with final interpretative hypotheses, both with regards the central theme, both with regard to the exemplary in-depth case corresponding to the Poppi castle.