Alpine peatlands aged 10 000 years old were cored in the Swiss Fimba Valley to investigate their development and past environmental conditions. Sediment layers embedded in the peat show periods of glacier growth, which suppressed peat growth. Human impacts like pastoralism and deforestation began shaping the landscape from the Bronze Age onwards into what it is today. The impacts and potential effects on carbon accumulation and flood mitigation in the valley should be considered in land management practice.