This strange friendship soon came to an end, and in the decades before and after the year 1000 we come across the Kalbite Amīr again in Southern Italy. In Sicily however the population experienced years of progress and prosperity under intelligent rulers. The general welfare was shewn most completely in the households of the Amīrs. The material prosperity of the Orient of the time, the refined style of living, the rich intellectual life of Court circles in Bagdad, Cordova, and Cairo, were also to be met with in Palermo, whose best period corresponds to the reign, unfortunately but too short, of the Amīr Yūsuf (989-998). But immediately after Yūsuf's decease indications began to appear which shewed that the Kalbite dynasty had passed its highest point of excellence. Yūsuf was rendered incapable of holding the reins of government by a stroke and his son Ja'far (998-1019) was not fortunate in his methods. The opposition between Arabs and Berbers, never quite extinct, now started up again. The revolt which followed ended with the expulsion of the Berbers and the execution of a brother of the Amīr, who had led them. Ja'far was however compelled to yield to another revolt, carried out by another brother. Thus weakened inwardly Sicily was no longer able effectively to resist the various hostile naval powers, such as Byzantium and Pisa, which threatened it; and early in the new century the Sicilian fleet suffered various defeats. It was not until the Zīrids allied themselves with the Sicilians that, during its third decade, more extended raids could be undertaken against the Byzantine lands, but these too always ended in defeat.
Added to these defeats there followed, from 1035 onwards, a civil war, which was the beginning of the end of the dynasty and also of the sway of Islām in Sicily. On this occasion the trouble was not between Arabs and Berbers, but was the consequence of the expulsion of the latter. The Berbers had to be replaced by other troops, and these of course cost money, so that the taxes had to be raised. The native population thereupon took up arms. The Amīr Aḥmad at this stage applied to Byzantium for assistance, whilst the rebels, who were led by a brother of the Amīr, called in the help of the Zīrids. The Byzantine general Maniakes, in whose army were numerous Normans, gained battle after battle (1038-1040), but then experienced difficulties with the Normans on account of his bad treatment of them, and also fell out with Stephanos the leader of the Byzantine fleet, so that all the fruits of their victories were lost to the Byzantines (up to 1042). The native population too had in the meantime forced the Zīrids, on account of their licentious behaviour, to return to Africa, so that there would really have been a good field for the revival of the Kalbite rule.
In the course of this general fight, each party against the others, the individual minor magnates and the towns had learned to fight for themselves, so that Sicily emerged from the great war no longer as an undivided State, but as a conglomerate of petty principalities and civic
