Research indicates that when people first came to Orkney relative sea-level may have been up to twenty metres below present. Since then it has slowly risen but the result is that the nature of the archipelago has changed dramatically throughout the time when people have lived here.
The first people to come to Orkney were small exploratory groups of Mesolithic hunter-gatherers from the Scottish Mainland. The first settlement is dated to around 8000 years ago, but it is likely that the islands had been thoroughly explored before that. These explorers crossed the Pentland Firth in small skin boats and found a landmass that comprised two main islands. They may have been drawn by favourable currents into Scapa Flow which would have provided safe anchorage, abundant resources and easy access to the rest of the island.
The Mesolithic communities of Orkney left little behind them. The red dots indicate the locations of Mesolithic findspots but only two sites have been excavated and dated. It is likely that these early communities stayed in touch with those on the Scottish Mainland. They were skilled seafarers and the Pentland Firth, though tricky, would not have posed a serious barrier. In Orkney, rising sea-levels resulted in the separation of individual islands, often surrounded by wide intertidal zones which would have been especially productive for the early hunter-gatherers.
Although the early inhabitants of Orkney had seen a period of relatively rapid sea-level change it had started to slow. The distances between island landmasses had increased and Scapa Flow was now open to the west as well as the east. Many of the extensive intertidal areas had started to diminish.
By 3500 BC farming was well established and the communities of Orkney were living in permanent settlements. Small tracts of coastal land remained to be inundated but the configuration of the islands was similar to that of today. Although the overall impact of sea-level rise was not great the loss of any farmland would be stressful and some areas would be more vulnerable than others. Nowhere was this more so than along the Brodgar Peninsula.