The History of the Decline and Fall of the Roman Empire was written by English historian Edward Gibbon and published in six volumes, covering the period of the Roman Empire after Marcus Aurelius, from 180 to 1453, concluding in 1590. They take as their material the behavior and decisions that led to the decay and eventual fall of the Roman Empire in the East and West, offering an explanation for why the Roman Empire fell. This work stands as a major literary achievement of the 18th century because it was adopted as a model for the methodologies of modern historians. This led to Gibbon being called the first modern historian of Ancient Rome. (source: Wikipedia)
Diligence and accuracy are the only merits which an historical writer may ascribe to himself; if any merit, indeed, can be assumed from the performance of an indispensable duty. I may therefore be allowed to say, that I have carefully examined all the original materials that could illustrate the subject which I had undertaken to treat. Should I ever complete the extensive design which has been sketched out in the Preface, I might perhaps conclude it with a critical account of the authors consulted during the progress of the whole work; and however such an attempt might incur the censure of ostentation, I am persuaded that it would be susceptible of entertainment, as well as information. At present I shall content myself with a single observation. The biographers, who, under the reigns of Diocletian and Constantine, composed, or rather compiled, the lives of the Emperors, from Hadrian to the sons of Carus, are usually mentioned under the names of Ælius Spartianus, Julius Capitolinus, Ælius Lampridius, Vulcatius Gallicanus, Trebellius Pollio and Flavius Vopiscus. But there is so much perplexity in the titles of the MSS., and so many disputes have arisen among the critics (see Fabricius, Biblioth. Latin. l. iii. c. 6) concerning their number, their names, and their respective property, that for the most part I have quoted them without distinction, under the general and well–known title of the Augustan History.