The Slavs and the Old Prussians. Poland in the Early Medieval Period / Славяне и Древние Пруссы. Польша в период Раннего Средневековья.: The difference between the archaeological record from the close of antiquity and that from the opening stages of the Karly Medieval Period is too great to be explained in terms of a demographic crisis which supposedly occurred on the turn of the 5th c. Th