The Turks, who, during all these years, had been making predatory excursions along the frontiers of Hungary, now, in three strong bands of ten thousand each, overran Servia and Bosnia, and spread their devastations even into the heart of Illyria, as far as the metropolitan city of Laybach. The ravages of fire and sword marked their progress. They burnt every village, every solitary cottage, and the inhabitants were indiscriminately slain. Frederic, the emperor, a man of but little energy, was at his country residence at Lintz, apparently more anxious, writes a contemporary, "to shield his plants from frost, than to defend his domains against these barbarians." The bold barons of Carniola, however, rallied their vassals, raised an army of twenty thousand men, and drove the Turks back to the Bosphorus. But the invaders, during their unimpeded march, had slain six thousand Christians, and they carried back with them eight thousand captives. Again, a few years after, the Turks, with a still larger army, rushed through the defiles of the Illyrian mountains, upon the plains of Carinthia. Their march was like the flow of volcanic fire. They left behind them utter desolation, smouldering hearth-stones and fields crimsoned with blood. At length they retired of their own accord, dragging after them twenty thousand captives. During a period of twenty-seven years, under the imbecile reign of Frederic, the very heart of Europe was twelve times scourged by the inroads of these savages. No tongue can tell the woes which were inflicted upon humanity. Existence, to the masses of the people, in that day, must indeed have been a curse. Ground to the very lowest depths of poverty by the exactions of ecclesiastics and nobles, in rags, starving, with no social or intellectual joys, they might indeed have envied the beasts of the field. The conduct of Frederic seems to be marked with increasing treachery and perfidy. Jealous of the growing power of George Podiebrad, he instigated Matthias, King of Hungary, to make war upon Bohemia, promising Matthias the Bohemian crown. Infamously the King of Hungary accepted the bribe, and raising a powerful army, invaded Bohemia, to wrest the crown from his father-in-law. His armies were pressing on so victoriously, in conjunction with those of Frederic, that the emperor was now alarmed lest Matthias, uniting the crowns of Hungary and Bohemia, should become too powerful. He therefore not only abandoned him, but stirred up an insurrection among the Hungarian nobles, which compelled Matthias to abandon Bohemia and return home.