罗马撤退原因之争

A proposed explanation for the Romans’ withdrawal from Britain, based on a study of tree ring data, is now being questioned by historians, discovers Michael Marshall RESEARCHERS are at odds over a claim that droughts helped trigger conflicts in late Roman Britain. Climatologists identified evidence of drought coinciding with unrest and battles, but historians say they have misread key written sources. In a study published last year, a team led by Ulf Büntgen, a geographer at the University of Cambridge, analysed tree ring data from oak trees from southern Britain and northern France to reconstruct the climate between AD 288 and 2009. The researchers identified a series of severe summer droughts in southern Britain between the years 364 and 366. …