 This division was replaced only in the beginning of 18th century when Peter I introduced guberniyas.Northwestern Russia – the lands near Ilmen Lake, Volkhov River, Ladoga Lake and Gulf of Finland, often referred to as "Novgorod volost" in chronicles, formed the core of the state.The assumptions of the internal structure of independent Novgorod are mostly based on the list of the builders of the Great Bridge over Volkhov (1260s) and the 1471 treaty between Novgorod and Casimir IV of Poland.