The taxes for which assessments exist include poll, hearth, land, window, tithe, marriage, birth and burial taxes. The Corporation's financial officer, the Chamberlain of London, acted as Government agent for the collection of many national taxes in London in the 17th and 18th centuries. The taxes, authorised by Acts of Parliament, were collected in the City's wards or parishes and the money was then transferred to the Exchequer in bulk payments. Sometimes, the Chamberlain acted as treasurer for an area larger than the City of London, and so the CLRO also has a few assessments for parishes in Westminster and Middlesex, and a very few other places in surrounding counties. Depending on the tax, most assessments were made by ward, some by parish.
Information can vary between different assessments.
The sparsest information can be merely lists of householders' names, sometimes without even street names or precinct divisions within the parish or ward. However, some assessments, such as the poll tax, required all inhabitants of each house to be listed. Some assessments include trades or occupations, but most do not. One of the most informative assessments is that for the tax on births, marriages and burials, and annual dues on bachelors over 25 years of age and on childless widowers, more commonly known as the 1695 Marriage Assessment. It is one of the few tax assessments in CLRO to have been indexed for personal names.