Introduction
The Migration Period in Europe (370-550 CE) was turbulent with the decline of the Western Roman Empire, the invasion of the Huns, war, famine, and shifting alliances between Germanic tribes, followed by a major climatic event in 536 CE and the Justinian plague (541-549). The ringforts on Öland (an island off the east coast of Sweden), dated to 200-800 CE has been seen as a prime example of the signs of the changing times during the Migration Period in Sweden. They have been investigated with prospection methods as part of the collaboration project Crisis Conflict Climate between Stockholm University, Linnaeus University and Kalmar County Museum sponsored by Riksbankens Jubileumsfond.
There are 18 ringforts on Öland (Figure 1a), characterised by massive circular or oval limestone walls 5-6 m in width and height, typically enclosing an area of dense stone house foundation...


