war.  The Khazars were once more called in as allies; and their Khan, Ziebel, who coveted the plunder of Tiflis, held an interview with the emperor in the sight of the Persians who guarded that town, adored his majesty, and received from his hands the diadem that adorned his own brow.  Richly entertained, and presented with all the plate used in the banquet, with a royal robe, and a pair of pearl earrings, promised moreover the daughter of the emperor (whose portrait he was shown) in marriage, the barbarian chief, dazzled and flattered, readily concluded an alliance, and associated his arms with those of the Romans.  A joint attack was made upon Tiflis, and the town was reduced to extremities; when Sarablagas, with a thousand men, contrived to throw himself into it, and the allies, disheartened thereby, raised the siege and retired.

Meanwhile, in Asia Minor, Theodore engaged the army of Shahen; and, a violent hailstorm raging at the time, which drove into the enemy’s face, while the Romans were, comparatively speaking, sheltered from its force, he succeeded in defeating his antagonist with great slaughter.  Chosroes was infuriated; and the displeasure of his sovereign weighed so heavily upon the mind of Shahen that he shortly afterwards sickened and died.  The barbarous monarch gave orders that his corpse should be embalmed and sent to the court, in order that he might gratify his spleen by treating it with the grossest indignity.

At Constantinople the Persian cause was equally unsuccessful.  Shahr-Barz, from Chalcedon, entered into negotiations with the Khan of the Avars, and found but little difficulty in persuading him to make an attempt upon the imperial city.  From their seats beyond the Danube a host of barbarians—­Avars, Slaves, Gepidas, Bulgarians, and others—­advanced through the passes of Heemus into the plains of Thrace, destroying and ravaging.  The population fled before them and sought the protection of the city walls, which had been carefully strengthened in expectation of the attack, and were in good order.  The hordes forced the outer works; but all their efforts, though made both by land and sea, were unavailing against the main defences; their attempt to sap the wall failed; their artillery was met and crushed by engines of greater power; a fleet of Slavonian canoes, which endeavored to force an entrance by the Golden Horn, was destroyed or driven ashore; the towers with which they sought to overtop the walls were burnt; and, after ten days of constantly repeated assaults, the barbarian leader became convinced that he had undertaken an impossible enterprise, and, having burnt his engines and his siege works, he retired.  The result might have been different had the Persians, who were experienced in the attack of walled places, been able to co-operate with him; but the narrow channel which flowed between Chalcedon and the Golden Horn proved an insurmountable barrier; the Persians had no ships, and the canoes of the Slavonians were quite unable to contend with the powerful galleys of the Byzantines, so that the transport of a body of Persian troops from Asia to Europe by their aid proved impracticable.  Shahr-Barz had the annoyance of witnessing the efforts and defeat of his allies, without having it in his power to take any active steps towards assisting the one or hindering the other.