A number of medieval sources attest to the presence of Slavs in Greece. While en route to the Holy Land in 732, Willibald "reached the city of Monemvasia, in the land of Slavinia". This particular passage from the "Vita Willibaldi" is interpreted as an indication of a Slavic presence in the hinterland of the Peloponnese. In reference to the plague of 744–747, Constantine VII wrote during the 10th century that "the entire country the Peloponnese was Slavonized". Another source for the period, the "Chronicle of Monemvasia" speaks of Slavs overrunning the western Peloponnese, but of the eastern Peloponnese, together with Athens, remaining in Byzantine hands throughout this period. However, such sources are far from ideal, and their reliability is debated. For example, while the Byzantinist Peter Charanis believes the "Chronicle of Monemvasia" to be a reliable account, other scholars point out that it greatly overstates the impact of the Slavic and Avar raids of Greece during this time.