To the difficulties caused by disaster, depopulation and maladministration there was added the danger of foreign invasion when war broke out in Europe between Francis I.
On the depopulation of Samaria and the introduction of colonists, see Winckler's objections, Alttest.
The 17th and 18th centuries, however, mark the worst period of depopulation in the more malarious parts of the Campagna, which seems to have begun in the 15th century, though we hear of malaria throughout the middle ages.
Disease and depopulation resulted from this policy and at the end of the 18th century the Legislative Assembly decided to reduce the area of the pools which then covered twice their present extent.
The depopulation of Spain dates certainly from the Moorish conquest, possibly from the earlier Visigothic invasion.