In short, the ambitious foreign policy of Justinian, the powers of nature, and the increasing boldness of the barbarians, contrived to make this period fatal to Greece. Yet the Emperor bestowed one signal benefit upon that country. By the importation of silkworms he gave the Greeks the monopoly, so far as Christendom was concerned, of a valuable manufacture, which was not infringed till the Norman invasion six centuries later. The history of Greece becomes very obscure after the death of Justinian, and the historian must be content to piece together from the Byzantine writers such stray allusions as those chroniclers of court scandals make to the neglected fatherland of the Greeks. The salient fact of this period is the recurrence of the Slav invasions of Justinian’s time. We learn that in 578 or 581 an army of 100,000 Slavonians “ravaged Hellas” and Thessaly[29]; in 589, under the Emperor Maurice, the Avars, according to the contemporary historian, Evagrios, “conquered all Greece, destroying and burning everything[30].” This passage has given rise to a famous controversy, which at one time convulsed not only the learned, but the diplomatic world. In 1830 a German scholar, Professor Fallmerayer, published the first volume of a _History of the Peninsula Morea during the Middle Ages_, in which he advanced the astounding theory that the inhabitants of modern Greece have “not a single drop of genuine Greek blood in their veins.” “The Greek race in Europe,” he wrote, “has been rooted out. A double layer of the dust and ashes of two new and distinct human species covers the graves of that ancient people. A tempest, such as has seldom arisen in human history, has scattered a new race, allied to the great Slav family, over the whole surface of the Balkan peninsula from the Danube to the inmost recesses of the Peloponnese. And a second, perhaps no less important revolution, the Albanian immigration into Greece, has completed the work of destruction.” The former of these two foreign settlements in the Peloponnese, that of the Slavs and Avars, was supposed by Fallmerayer to have taken place as the result of the above-mentioned invasion of 589, and his supposition received plausible confirmation from a mediæval document. The Patriarch Nicholas, writing towards the end of the eleventh century to the Emperor Alexios I Comnenos, alludes to the repulse of the Avars from before the walls of Patras in 807, and adds that they “had held possession of the Peloponnese for 218 years (_i.e._ from 589), and had so completely separated it from the Byzantine Empire that no Byzantine official dared to set his foot in it[31].” A similar statement from the _Chronicle of Monemvasia_[32]—a late and almost worthless compilation—was also unearthed by the zealous Fallmerayer, who accordingly believed that he had proved the existence of a permanent settlement of the Peloponnese by the Slavs and Avars between 589 and 807, “in complete independence of the Byzantine governors