These facsimiles were made when the papyrus rolls from Herculaneum were first opened. Most of the work was carried out at Portici near Naples from 1802 to 1806 under the direction of the Rev. John Hayter and at the expense of the Prince of Wales (later George IV). In many places the drawings preserve text no longer present in the original papyri: fragments of papyrus that had become stuck to a lower layer during the unrolling process were drawn and then scraped off in order to reveal the letters underneath. Such fragments, and others lost through subsequent damage to the originals, are known only from these drawings. For a recent brief treatment of the role of these drawings in the study of the papyri, see K. Fleischer, Die Papyri Herkulaneums im Digitalen Zeitalter (Berlin 2022) 35–7.
This set of facsimiles is kept in the Bodleian Library. They are bound in seven volumes (MS. Gr. class. c. 1–7), and the leaves are numbered consecutively in a single series. The database is an updated version of one originally made available by the Herculaneum Society on the Faculty of Classics website.