Alexius Comnenus found himself, in 1081, placed in a position almost as difficult and perilous as that which Leo the Isaurian faced in 716. Like Leo, he was a usurper without prestige or hereditary claims, seated on an unsteady throne, and forced to face imminent danger from the Moslem enemy without, and from rival adventurers within. It may be added that the Isaurian, grievously threatened as he was by the enemy from the East, had no peril impending from the West. Alexius had to face at one and the same time the assault of the Seljouks on Asia Minor, and the attack of a new and formidable foe in his western provinces. We have already mentioned the manner in which the Byzantine dominion in Italy had come to an end. Now the same Norman adventurers who had stripped the empire of Calabria and Apulia were preparing to cross the straits of Otranto, and seek out the Emperor in the central provinces of his realm. The forces of the Italian and Sicilian Normans were united under their great chief Robert Guiscard, the hardy and unscrupulous Duke of Apulia. Just ten years before he had captured Bari, the last Byzantine fortress on his own side of the straits; now he was resolved to take advantage of the anarchy which had prevailed in the empire ever since the day of Manzikert, and to build up new Norman principalities to the east of the Adriatic. There seemed to be nothing presumptuous in the scheme to those who remembered how a few hundred Norman adventurers had conquered all Southern Italy and Sicily, and swelled into a victorious army fifty thousand strong. Nor could the invaders fail to remember how, but fifteen years before, another Norman duke had crossed another strait in the far West, and won by his strong right hand the great kingdom of England. Alexius Comnenus sat like Harold Godwinson on a lately-acquired and unsteady throne, and Duke Robert thought to deal with him much as Duke William had dealt with the Englishman. In June, 1081, the Normans landed, thirty thousand strong, and laid siege to Durazzo, the maritime fortress that guarded the Epirot coast. The Emperor at once flew to its succour. Always active, hopeful, and versatile, he trusted that he might be able to beat off the new invaders, whose military worth he was far from appreciating at its true value. He patched up a hasty pacification with Suleiman, Sultan of the Seljouks, by surrendering to him all the territory of which the Turk was in actual possession, a tract which now extended as far as the waters of the Propontis, and actually included the city of Nicaea, close to the Bithynian shore, and only seventy miles from Constantinople.