Modern narratives about changes in the Italian landscape during the early Middle Ages have often been based on assumptions about changing demography; the loss and replacement of complex Roman economic, political and agricultural systems; and broader changes in climate. Using fossil pollen taken from lake cores in the Rieti basin to reconstruct local ecological conditions, close examinations of two discreet periods offer new insights into the changes from small-scale agriculture to silvo-pastoralism that began during the late sixth and early seventh centuries. The deforestation of the ninth century, accompanied by an increase in cultivation, was the result of a long-term accumulation of territory under monastic control. The fact that these changes in the landscape run counter to the prevailing climatic conditions underscores the success of human management of the environment.