Chapter and footnote numbers follow Professor Womersley’s edition, both hardcover and paperback. (Some editors have disrupted Gibbon’s sequences by inserting numbered footnotes of their own.) Gibbon’s footnote quotations are mostly in Greek and Latin, some in French and a few in Italian. The only systematic English translations I have found, sometimes quoted herein, are by Anthony Lentin and Brian Norman, in an abridged edition of the Decline and Fall (Wordsworth 1998), “unless [the passages were] already translated or substantially paraphrased by Gibbon in the body of his text.” (p xv). Generally I use Loeb Library (Harvard University) translations of the classics. An impressive number of translations of his medieval sources, however obscure, have been published. I have traced many of Gibbon’s unsourced quotations online, including in the Thesaurus Linguae Graecae. Apparent quotations by him are sometimes paraphrases or change inflection or tense, making the original passages very hard to identify with certainty. Certain original sources Gibbon cites are now considered by some scholars as pseudonymous or forgeries, such as some letters by the Emperor Julian. Gibbon used a number of 17th & 18th century Greek texts which included parallel Latin translations. Gibbon rarely quotes secondary sources, although he usually acknowledges them for the originals he was unable to see for himself.
The translations here are offered only to help the reader “form some idea” of the originals. (see 5 n 6) Almost all originals were manuscripts with illegible words and phrases subject to different, equally plausible, readings. The published translations quoted here appear sometimes to be of original texts edited differently from those Gibbon used. Gibbon was not shy to emend published Greek and Latin texts.
There is much room for a team of specialists in classical, medieval, Byzantine, and Renaissance linguistics and literature to identify the specific editions quoted by Gibbon; evaluate the merits of his emendations; assess his grasp of Latin and Greek in word and spirit; and translate the quotations on the literal end of the spectrum, for comparison to his own translations and paraphrases in his famously distinctive English style.