Emerging mediaeval heritage: Environmental history research at Băgău (c. Alba, Romania) and the Bottomless Lake (Tăul fără fund)

The investigation of a 8.1 m long peat sequence from Tăul fără fund (“Bottomless Lake,” Transylvanian Basin, Northern Romania) offers a series representing wetland development since the Middle Holocene. The most striking feature of the sequence is a cca. 900 year-long hiatus caused by peatcutting in the 14th century AD. An artificial reservoir was constructed there in the Late Middle Ages by the excavation of the uppermost peat layer, afflicting a significant environmental impact on this remote location. One of the oldest documented Hungarian settlements from the time of the Hungarian Kingdom (11th century AD, presumably with previous history) in Transylvania was discovered in the vicinity of the former reservoir by an archaeological field survey. By harmonising historical data and the exact chronological sequence of the borehole, the creation of the reservoir was inserted into the local history of the developing mediaeval settlement network at the time when some of the early settlements had been abandoned and a permanent village was established, with a church and upscale landowners, in the area of present-day Băgău in the 13th to 14th century AD. Significant environmental impacts have emerged during this transitional period around the reservoir.