The paper outlines the genesis and subsequent transformation of the database Calendar of London Concerts 1750–1800, now available as a dataset at https://www.doi.org/10.17026/dans-znv-3c2j. Originally developed during the 1980s, the database was used as a primary research tool in the preparation of articles and a 1993 monograph: the first comprehensive study of London’s flourishing public concert life in the later eighteenth century, which culminated in Haydn’s London visits in 1791–5. The database itself, extending to over 4000 records, was derived from an exhaustive study of London newspapers. Following the obsolescence of the relational database in which the material was initially stored, it has recently been transferred to a spreadsheet in csv format, publicly available with free open access. Issues arising out of the standardisation of concert data are explored, especially regarding the layout of complete concert programmes, and the strengths and limitations of the original design are analysed, within the context of the newly available version.