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, 2014. © 2014 Wiley Periodicals, Inc.