The tax was levied twice a year –at Lady Day and Michaelmas –between 1662 and 1688.During this time it was the government’s major source of revenue. The tax was introduced because it was “easy to tell the number of hearths, which remove not as heads or polls do”. Each hearth was taxed at the rate of two shillings a year payable in two instalments. Those people who were too poor to be rated to church and poor rates, or who occupied premises worth less than twenty shillings a year, or who possessed property worth not above £10 were exempt. Only the return for Pirton 1663 is included in this database. Although two more survive they are difficult to read. The returns are held in the National Archives at Kew [E179] but HALS has the Hertfordshire records on microfilm.