did not pay the Zakaat tax. The conquered population could instead pay the Zakaat tax by converting to Islam. Large numbers of native Sicilians converted to Islam. However, even after 100 years of Islamic rule, numerous Greek-speaking Christian communities prospered, especially in north-eastern Sicily, as dhimmis. This was largely a result of the Jizya system which allowed co-existence. This co-existence with the conquered population fell apart after the reconquest of Sicily, particularly following the death of King William II of Sicily in 1189. By the mid-11th century, Muslims made up the majority of the population of Sicily. Emirates in Apulia From Sicily, the Muslims launched raids on the mainland and devastated Calabria. In 835 and again in 837, the Duke of Naples was fighting against the Duke of Benevento and appealed to the Sicilian Muslims for help. In 840 Taranto and Bari fell to the Muslims, and in 841 Brindisi. Muslim attacks on Rome failed in 843, 846 and 849. In 847 Taranto, Bari and Brindisi declared themselves emirates independent from the Aghlabids. For decades the Muslims ruled the Mediterranean and attacked the Italian coastal towns. Muslims occupied Ragusa in Sicily between 868 and 870. Only after the fall of Malta in 870 did the occidental Christians succeed in setting up an army capable of fighting the Muslims. Over the next two decades, most of the territory held by Muslims on the mainland was liberated from Muslim rule. The Franco-Roman emperor Louis II reconquered Brindisi in 869, Bari in 871 and beat the Arabs at Salerno in 872. The Byzantines retook Taranto in 880. In 882 the Muslims had founded at the mouth of Garigliano between Naples and Rome a new base further in the north, which was in league with Gaeta, and had attacked Campania as well as Sabinia in Lazio. In 915, Pope John X organised a vast alliance of southern powers, including Gaeta and Naples, the Lombard princes and the Byzantines. The subsequent Battle of the Garigliano was successful, and all Saracens were captured and executed, ending any presence of Arabs in Lazio or Campania permanently. A hundred years later, the Byzantines called the Sicilian Muslims to ask for support against a campaign of German emperor Otto II. They beat Otto at the battle of Stilo in 982 and for the next 40 years largely succeeded in preventing his successors from entering southern Italy. In 1002 a