attacks from the north. In 828 Crete fell to Arab pirates from Spain, and throughout the ninth century the western seaboards of the empire were subjected to raids by the Aghlabids. The prosperous island of Sicily was invaded in 827, and after the fall of the capital, Syracuse, in 878, only a few outposts in the eastern part of the island remained in Greek hands. Danger closer to home was posed by the Bulgars, who exploited the collapse of Avar power to build up a strong state in which a Bulgar aristocracy ruled a Slav peasantry. Macabre proof of the Bulgar threat came in 811 when the Khan Krum defeated the Emperor Nicephorus I and had his skull made into a drinking goblet. Ironically, the Bulgar menace proved most serious later in the century after Byzantine missionaries began a programme of conversion to orthodox Christianity; equipped with a more elaborate administration and a hybrid culture stimulated by the introduction of a Slavonic alphabet, the Bulgar state under Tsar Symeon challenged the universality of Byzantium by presenting itself as a legitimate rival empire. Byzantium also faced raids from another northern neighbour, the Rus, Scandinavian adventurers who had established an ascendancy over the Slav population of Russia and who resembled their Viking cousins in the west by combining lucrative trading with destructive raiding.
Gradually, however, Byzantium emerged from its heroic period with its prestige, power, and wealth greatly increased. Byzantine naval power enabled it to reassert its authority over Dalmatia and Venice, and in 876 the first emperor of the Macedonian dynasty, Basil I, exploited the weakness of the Lombard princes of southern Italy in the face of Arab raids to occupy Bari and establish themes in Calabria and Langobardia (modern Apulia). Earlier in the century Byzantine generals had conquered the Slav territories of the Peloponnese and a process of Christianization and Hellenization was undertaken by Greek monks. At home the empire had recovered from the selfinflicted wounds of the iconoclast controversy and enjoyed a period of relative stability under the Macedonians. Equally important was the empire's evolution of a realistic and imaginative policy towards its northern neighbours. The
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