 Complete the following phrase:  Around 200 years after the Boldon Book, Thomas Hatfield - Bishop of Durham from 1345-1381, commissioned the Hatfield survey. This was a more comprehensive population survey which again combined Cleadon and Whitburn as a single parish. The survey reveals changes in land ownership, including the introduction of copyhold tenure and bondsmen. Between the 12th and 14th centuries, the region suffered from the plague which first broke out in 1230s and culminated in the 