It may surprise some readers that frontier methods such as Data Envelopment Analysis (DEA) can be used to assess the productive efficiency of the estates of eleventh century England. This is possible because in 1086, William the Conqueror carried out a comprehensive survey (the Domesday Survey) of lands he invaded 20 years earlier. The survey provides high-quality data on the inputs and outputs of most manors in England. A previous analysis of the data for Essex estates indicated that the average efficiency of the Domesday agricultural economy was comparable to, if not higher than that for more modern economies, that some tenants-in-chief displayed significantly more entrepreneurial flair than others, and that the geographical location, the size of the estate and the arable/livestock mix all significantly affected estate efficiency. In this article, analysis of a second Domesday county, Wiltshire, confirms the general results for Essex, but indicates some differences in the factors affecting estate efficiency.