Atto da Pistoia (last decades of the eleventh century-1153), abbot general of the Benedictine Vallombrosan monks and bishop of Pistoia, a local saint recognised as such from the seventeenth century onwards, was a churchman and hagiographer, a contemplative man, and an active pastor in the religious and political life of his time. He is undoubtedly one of the most interesting and perhaps least known figures of the twelfth century. The paper highlights his characteristics as a man of government, above all as the leader of the Vallombrosan Order, whose institutional structures, hagiographic memory and territorial diffusion in Central-Northern Italy and Sardinia he consolidated, taking into account the most recent historiographical investigations on the personage and the perspectives of interpretation opened up by research on Vallombrosan monasticism.