In 1655, after the extinguishing battle, for the first time in history the Lithuanian capital Vilnius was taken by a foreign army. The Russian army looted the city, splendid churches, and manors. Between 8,000 and 10,000 citizens were killed; the city burned for 17 days. Those who returned after the catastrophe could not recognise the city. The Russian occupation of the Grand Duchy of Lithuania lasted up to 1661. Many artefacts and cultural heritage were either lost or looted, significant parts of the state archive – Lithuanian Metrica, collected since the 13th century, were lost and the rest was moved out of the country. During the Northern Wars (1655–1661), the Lithuanian territory and economy were devastated by the Swedish army. Almost all territory of the Grand Duchy of Lithuania was occupied by Swedish and Russian armies. This period is known as "Tvanas" (The Deluge).