AbstractFossil tundra fragments consisting chiefly of moss (Rhacomitrium lanuginosum—60%,Dicranum—20 %) were found in the forefield of Werenskioldbreen during the glaciological investigations of the Polish Scientific Spitsbergen Expedition. The vegetation formed a cover about 5 cm thick and occurred between two till layers. The samples taken for radiocarbon analysis in 1973 came from a position 25 m a.s.l., located about 450 m from the glacier front. In 1957 the fossil tundra was still completely covered by ice. The average age of the whole stratum was dated to 1080±105 years B.P. (St-4695). The age of the upper part of this layer was dated to 760±145 years B.P. (Gd-264), and the lower part to 1565±235 (St-5068). Tundra fragments of similar age (1–7578: 1095±85 years B.P.) have also been found between two till layers at the front ofÅrjep Ruotesjekna in Swedish Lapland.The results indicate that during the Viking Age Spitsbergen and northern Scandinavia experienced a warm period with distinct glacier retraction and well-developed tundra on the glacier forefields. This period was preceded by a marked, long-lasting glacier advance and followed by an equally extensive, but shorter advance.