Isotope variations were studied in necropolises of the early (6th to 7th century CE) and central (10th to 11th century CE) medieval period located in Fruili-Venezia Giulia (Northeastern Italy). The two periods each shortly followed two great barbarian invasions that changed the politics and economy of Italy: the arrivals of Langobards in 578 CE and the Hungarian incursions from the end of the 9th to the first half of the 10th century. These events had a tragic effect on the economy of Friuli-Venezia Giulia: severe depopulation and the partial abandonment of the countryside with fall of agricultural production. Am J Phys Anthropol 154:561–574, 2014. © 2014 Wiley Periodicals, Inc.