The Norse arriving from Greenland settled Greenland from approximately 980 to 1450. The Norse arrived in southern Greenland prior to the 13th century approach of Inuit Thule people in the area. The extent of the interaction between the Norse and Thule is unclear. Greenland was valuable to the Norse due to trade of ivory that came from the tusks of walruses. The Little Ice Age adversely affected the colonies and they vanished. Greenland would be lost to Europeans until Danish Colonization in the 18th century.