cause. On the continuity of the Roman Empire depended the unity of his work. By the emphasis laid on this fact he did the same kind of service to the study of history in England, that Mr. Bryce has done in his Holy Roman Empire by tracing the thread which connects the Europe of Francis the Second with the Europe of Charles the Great.
Gibbon read widely, and had a large general knowledge of history, which supplied him with many happy illustrations. It is worth pointing out that the gap in his knowledge of ancient history was the period of the Diadochi and Epigoni. If he had been familiar with that period, he would not have said that Diocletian was the first to give to the world the example of a resignation of sovereignty. He would have referred to the conspicuous case of Ptolemy Soter; Mr. Freeman would have added Lydiadas, the tyrant of Megalopolis. Of the earlier example of Asarhaddon Gibbon could not have known.
New method of research To pass from scope and spirit to method, Gibbon's historical sense kept him constantly right in dealing with his sources, but he can hardly be said to have treated them methodically. The growth of German erudition is one of the leading features of the intellectual history of the nineteenth century; and one of its most important contributions to historical method lies in the investigation of sources. German "Quellenkritik" scholars have indeed pressed this "Quellenkunde" further than it can safely be pressed. A philologist, writing his doctoral dissertation, will bring plausible reasons to prove where exactly Diodorus ceased to "write out" Ephorus, whose work we do not possess, and began to write out somebody else, whose work is also lost to us. But, though the method lends itself to the multiplication of vain subtleties, it is absolutely indispensable for scientific historiography. It is in fact part of the science of evidence. The distinction of primary and derivative authorities might be used as a test.