The conservation department at the National Library of Wales, working on tithe maps from the 1840s.

Tithe maps were produced between 1838 and 1850 following the Tithe Commutation Act of 1836 as a part of the process to ensure that all tithes were paid with money rather than produce. They are the most detailed maps of their period and there are over a thousand of them covering more than 95% of Wales.