The need for hydrological and geological planning in the lands of the province of Naples had already been recognized by the Romans in Republican era who, through the centuriatio, created effective networks of canalization and water drainage. After the devastation caused in the late ancient era by the Goths and Vandals, in the 13th century a renewed awareness of the need to pursue environmental and territorial protection policies gradually began to resurface. The present contribution aims to investigate some of the most significant occurrences of territorial and environmental reclamation activity starting from the initiatives promoted by the legislation of Frederick II for environmental health, up to the policies implemented by Ferdinand II of Bourbon in the territories of the Phlegraean Fields and the so-called Terra di Lavoro.