The Pitted Ware culture arose around 3,500 BC. Its earliest sites are found in east-central Sweden, where it appears to have replaced the Funnelbeaker culture. Its subsequent expansion is accompanied by the disappearance of settlements of the Funnelbeaker culture throughout large parts of southern Scandinavia. It came to occupy the coasts of Denmark, southern Sweden, southern Norway and various islands of the Baltic Sea, such as Öland, Gotland, and Åland. There were lively contacts with hunter-gatherer communities of Finland and the eastern Baltic. During its initial years, the Pitted Ware culture co-existed with the Funnelbeaker culture. Although the two cultures exchanged goods with each other, its peoples appear to have had widely different identities, and they did not mix with each other to any notable extent. During the period of Pitted Ware expansion, the Funnelbeakers constructed a number of defensive palisades, which may mean that the two peoples were in conflict with each other. Throughout its existence of more than 1,000 years, the Pitted Ware culture remained virtually unchanged.