or a breach with the empire might have been precipitated. The final disavowal of the supremacy of the Constantinopolitan monarch was to be still delayed for nearly two hundred years. The wars between the Exarchs of Ravenna and the Lombard kings were little influenced by interference from the East. The emperors during the last thirty years of the sixth century were far more engrossed with their Persian and Slavonic wars. Contests with the Great king of the East occupied no less than twenty years in the reigns of Justin II., Tiberius, and Maurice. War was declared in 572, and did not cease till 592. Like the struggle between Justinian and Chosroës I., thirty years before, it was wholly indecisive. There were more plundering raids than battles, and the frontier provinces of each empire were reduced to a dreadful state of desolation and depopulation: if the Persians pushed their ravages as far as the gates of Antioch, Roman generals penetrated deep into Media and Corduene, where the imperial banner had not been seen for two hundred years. The net result of the whole twenty years of strife was that each combatant had seriously weakened and distressed his rival, without obtaining any definite superiority over him. Forced to make peace by the pressure of a civil war, Chosroës II. gave back to Maurice the two frontier cities of Dara and Martyropolis, the sole trophies of twenty campaigns, and ceded him a slice of Armenian territory. But these trivial gains were far from compensating the empire for the fearful losses caused by dozens of Persian invasions. The Persian war was exhausting, but successful: on the northern frontier, however, the Roman army had been faring far worse, and serious losses of territory were beginning to take place. The enemies in this quarter were two new tribes, who appeared on the Danube after the Lombards had departed from it to commence their invasion of Italy. There were now no Teutons left on the northern frontier of the empire: of the incoming tribes, one was Tartar and the other Slavonic. The Avars were a nomadic race from Asia, wild horsemen of the Steppes, much like their predecessors the Huns. They had fled west to escape the Turks, who were at this time building up an empire in Central Asia, and betook themselves to the South Russian plains, not far from the mouth of the Danube. To cross the river and ravage Moesia was too tempting a prospect to be neglected, and ere long the Avaric cavalry were seen only too frequently along the Balkans and on the coast of the Black Sea. Their first raid into Roman territory fell into the year 562, just before the death of Justinian, and from that time forward they were always causing trouble. They were ready enough to make peace when money was paid them, but as they invariably broke the agreement when the money was spent, it was never long before they reappeared south of the Danube.