The spelling of Catherine’s surname varies in newspapers, but has been standardized to the correct version, Tylney (as opposed to Tilney).
All quotations are cited in the references at the end of the book, but a few have been standardized and updated to modern English for the ease of understanding and clarity.
Money plays a huge part in Catherine’s story, but conversions over time are notoriously difficult. The Bank of England currency converter bases its calculations on average inflation of two per cent per year, estimating that £100 in 1810 is equivalent to around £7,000 in 2010 (i.e. multiply by 70). Very conservatively speaking, therefore, the Bank of England calculates that Catherine’s annual income of £40,000 would convert to around £2,500,000 today. This method is unreliable, however, because certain costs have soared disproportionately, such as house prices and rents. This is highlighted by the fact that in 1825, Catherine’s husband bought a detached villa in Hall Place (now Hall Gate), set in two acres adjoining Regent’s Park, for £6,000. Using the Bank of England converter, this villa would be worth around £320,000 in the early twenty-first century, when in reality a property like this would now fetch tens of millions of pounds. These soaring values must also factor into the equation, because Catherine’s assets were largely tied to land and property. So, in efffect, accurate monetary comparison is unfeasible and Catherine was far richer than the Bank of England conversion rates imply.
Throughout this book, I multiply by 100 to provide rough twenty-first-century equivalents. Even this, I believe, is conservative when calculating Catherine’s income.