Three centuries of English crop yields, 1211-1491

This is the single largest and most precise body of data on pre-modern grain harvests currently available internationally.  The raw information comes from thousands of precisely dated manorial accounts preserved in many public and private archives in England and beyond which record in minute detail the cultivation of seigniorial demesnes.  The accounts are hand written on parchment in abbreviated Latin using Roman numerals [for an example see “The data”] and state for each crop cultivated the quantities of grain seeded and harvested, sometimes including the medieval auditor’s own calculation of the rate at which the seed yielded (the yield per seed or yield ratio). The current database contains approximately 30,000 individual yield observations [see “Database”] which probably represent between two-thirds and three-quarters of all the observations potentially retrievable from the archives. The earliest information relates to the harvest of 1211 on the estates of the bishops of Winchester and the latest to that of 1491 on the estate of Battle Abbey.  Chronological coverage is, however, most continuous and comprehensive for the 160-years 1270 to 1430, a period marking the transition from the Medieval Climatic Optimum to the Little Ice Age and punctuated by the worst crises of subsistence and public health (the Great Famine of 1315-21 and Black Death of 1347-50) in recorded English and European history.

The painstaking task of transcribing this information from the original documents and making and tabulating the relevant yield calculations has taken several historians — most notably Jan Titow, David Farmer, and Bruce Campbell [see “Sources”] — many years.  Their hitherto separate and largely unpublished calculations are here combined into a single electronic database for the first time.  The database is the creation of Bruce M. S. Campbell, Professor of Medieval Economic History within the School of Geography, Archaeology, and Palaeoecology at The Queen’s University of Belfast (QUB). Funding has been provided by the Economic and Social Research Council (ESRC) – grant RES-000-23-0645 — British Academy and Sussex Archaeological Society.  Methodological advice has been provided by Professor Gregory Clark of the University of California at Davis and technical support by the Centre for Data Digitisation and Analysis, QUB. Copyright permission to release the unpublished yield calculations of the late David Farmer has been granted by the University of Saskatchewan Archives and to reproduce the published pre-1350 Winchester yields by Dr Jan Titow [see “Acknowledgements”].

The “Database” may be searched by crop, harvest year, manor, estate, county, region, and any combination of the same.  All that is required is that users identify themselves by registering. The yields given are yields per seed, gross of tithe (assumed to have been every tenth sheaf deducted in the field) and net of seed.  The database cannot be amended but a “Wiki” page is available where any corrections and additions can be noted along with other relevant comments. It is anticipated that the database will be corrected, added to, and extended as more data become available.  Meanwhile, the “Chronologies” facility offers a series of reconstructed annual chronologies for each of the principal crops and combinations of the same.  These have no counterpart for any other country or period before the 19th century and will be of particular value to archaeologists, historians, economists, environmentalists, and agronomists.  They have been derived from the spatially and chronologically discontinuous raw yield data using the regression facility available within the STATA statistical software package.