Tribes who poured into Eastern Europe in the sixth century blocked the old trading links between Scandinavia and Byzantium, the river routes that tracked across what is now Russia. Any goods that Scandinavians wanted had to come by some other route and from some other source, and so they came up from Frisia; in the two centuries before the Viking times began around 800 CE, everything that we know reached Scandinavia came by way of Frisian traders.15
