North Sea has provided waterway access for commerce and conquest. Many areas have access to the North Sea because of its long coastline and the European rivers that empty into it. There is little documentary evidence concerning the North Sea prior to the Roman conquest of Britain in 43 CE, however archaeological evidence reveals diffusion of cultures and technologies from across or along the North Sea to Great Britain and Scandinavia and a reliance by some prehistoric cultures on fishing, whaling, and seaborne trade on the North Sea. The Romans established organised ports in Britain, which increased shipping, and began sustained trade and many Scandinavian tribes participated in raids and wars against the Romans and Roman coinage and manufactures were important trade goods. When the Romans abandoned Britain in 410, the Germanic Angles, Frisians, Saxons, and Jutes began the next great migration across the North Sea during the Migration Period. They made successive invasions of the island from what is now the Netherlands, Denmark, and Germany.