The Muslim Aghlabids conquered Sicily between June 827 and 902, when the last major Byzantine stronghold on the island, Taormina, fell. Isolated fortresses remained in Byzantine hands until 965, but the island was henceforth under Arab Muslim rule until it was conquered in turn by the Normans in the late 11th century.
Although Sicily had been raided by the Muslim Arabs since the mid-7th century, these raids did not threaten Byzantine control over the island, which remained a largely peaceful backwater. The opportunity for the Aghlabid emirs of Ifriqiya (present-day Tunisia) came in 827, when the commander of the island's fleet, Euphemius, rose in revolt against the Byzantine emperor Michael II. Defeated by loyalist forces and driven from the island, Euphemius sought the aid of the Aghlabids, an Arab dynasty. The latter regarded this as an opportunity for expansion and for diverting the energies of their own fractious military establishment and alleviating the criticism of the Islamic scholars by championing jihad, and dispatched an army to aid him. Following the Arab landing on the island, Euphemius was quickly sidelined. An initial assault on the island's capital, Syracuse, failed, but the Muslims were able to weather the subsequent Byzantine counter-attack and hold on to a few fortresses. With the aid of reinforcements from Ifriqiya and Umayyad al-Andalus, in 831 they took Palermo, which became the capital of the new Arab-Muslim province.
The Byzantine government sent a few expeditions to aid the locals against the Muslims, but preoccupied with the struggle against the Abbasids on their eastern frontier and with the Cretan Saracens in the Aegean Sea, it was unable to mount a sustained effort to drive back the Muslims, who over the next three decades raided Byzantine possessions almost unopposed. The strong fortress of Enna in the centre of the island was the main Byzantine bulwark against Muslim expansion, until its capture in 859. Following its fall, the Muslims increased their pressure against the eastern parts of the island, and, after a long siege, captured Syracuse in 878. The Byzantines retained control of some fortresses in the north-eastern corner of the island for some decades thereafter, and launched a number of efforts to recover the island until well into the 11th century, but were unable to seriously challenge Muslim control over Sicily. The fall of the last major Byzantine fortress, Taormina, in 902, is held to mark the completion of the Muslim conquest of Sicily.
Under Arab rule, Sicily prospered and eventually detached itself from Ifriqiya to form a semi-independent emirate. The island's Muslim community survived the Norman conquest in the late 11th century and even prospered under the Norman kings, giving birth to a unique cultural mix, until it was deported to Lucera in the 1220s after a failed uprising.
Background
Throughout the imperial Roman period, Sicily was a quiet, prosperous backwater. Only in the 5th century did it suffer from raids by the Vandals operating from the coasts of Vandalic Africa. In 535, the island came under Byzantine control and was raided by the Ostrogoths in the Gothic War, but calm returned thereafter. Protected by the sea, the island was spared the ravages inflicted on Byzantine Italy through the Lombard invasions of the late 6th and early 7th centuries, and retained a still flourishing urban life and a civilian administration. It was only the increasing threat of the Muslim expansion that thrust it into the limelight. As John Bagnell Bury writes, "A fruitful land and a desirable possession in itself, Sicily's central position between the two basins of the Mediterranean rendered it an object of supreme importance to any Eastern sea-power which was commercially or politically aggressive; while for an ambitious ruler in Africa it was the steppingstone to Italy and the gates of the Adriatic."
Consequently, the island was early on targeted by the Muslims, the first raid occurring in 652, only a few years after the establishment of the first Muslim navy. Following the onset of Muslim attacks against North Africa, it became a crucial strategic base, and for a while, in 661–668, it was the residence of the imperial court under Constans II. Constituted as a theme around 690, its governing strategos also came to assume control over the scattered imperial possessions in the southern Italian mainland. The island was raided thereafter, especially in the first half of the 8th century, but did not come under serious threat until the Muslims completed their conquest of North Africa and moved into Hispania as well.
It was Abd al-Rahman al-Fihri, the Arab Abbasid governor of Ifriqiya, who first made plans to invade the island in force and attempt to capture it and Sardinia in 752–753, but he was thwarted by a Berber rebellion.
In 799, the founder of the Aghlabid dynasty, Ibrahim ibn al-Aghlab, secured recognition of his position as autonomous emir of Ifriqiya by the Abbasid caliph, Harun al-Rashid, thereby marking the establishment of a practically independent state centred on modern Tunisia. In 805, Ibrahim concluded a ten-year truce with the Byzantine governor of Sicily, which was renewed by Ibrahim's son and successor Abdallah I in 813. During this time, the Aghlabids were too preoccupied with their rivalry with the Idrisids, Arab dynasty, to the west to plan any serious assault on Sicily. Instead, there are testimonies of commercial traffic between Sicily and Ifriqiya, and of the presence of Arab traders on the island.
Euphemius' rebellion
The occasion for the invasion of Sicily was provided by the rebellion of the tourmarches Euphemius, commander of the island's fleet. According to later and possibly fictional accounts, driven by lust for a nun, he had forced her to marry him. Her brothers protested to Emperor Michael II, and the Byzantine ruler ordered the island's strategos, Constantine Soudas, to investigate the matter and if the charges were found true, to cut off Euphemius' nose as punishment. Thus it came that Euphemius, returning from a naval raid against the African coast, learned that he was to be arrested. Instead, he sailed for Syracuse, occupying the city, while the governor sought refuge in the interior. Euphemius soon managed to gain the support of a large part of the island's military leadership. Euphemius repulsed an attempt by Constantine to recover Syracuse, forcing the governor to flee to Catana. Euphemius' forces pursued and drove Constantine out of Catana, and eventually captured and executed him. Euphemius was then proclaimed emperor. The historian Alexander Vasiliev doubts the "romantic" story of the origin of Euphemius' revolt, and believes that the ambitious general simply used an opportune moment, when the central Byzantine government was weakened by the recent Revolt of Thomas the Slav, and by its preoccupation with the contemporary Muslim conquest of Crete, to seize power for himself.
At this point, however, Euphemius was deserted by one of his closest and most powerful allies, a man known through Arab sources as "Balata" (according to Vasiliev probably a corruption of his title, while Treadgold holds that he was named Plato), and his cousin Michael, commander of Palermo. The two men denounced Euphemius' usurpation of the imperial title and marched against Syracuse, defeated Euphemius and took the city.
Like one of his predecessors, Elpidius, who had rebelled under Irene of Athens, Euphemius resolved to seek refuge among the Empire's enemies and with a few supporters sailed to Ifriqiya. There he sent a delegation to the Aghlabid court, which pleaded with the Aghlabid emir Ziyadat Allah for an army to help Euphemius conquer Sicily, after which he would pay the Aghlabids an annual tribute. This offer came as a great opportunity for the Aghlabids, who faced long-simmering ethnic tensions between Arab settlers and Berbers, dissension and rebellions within the Arab ruling elite (the jund), and criticism for their preoccupation with worldly concerns, their "un-Islamic" system of taxation and their luxurious lifestyle from the jurists of the Malikite school. Indeed, at the time of Euphemius' arrival, Ziyadat Allah had just suppressed a dangerous three-year revolt of the jund under Mansur al-Tunbudhi. As Alex Metcalfe writes, "by undertaking a jihad to expand the frontiers of Islam at the expense of the infidels by conquest – the first major undertaking since the invasion of the Iberian Peninsula from 711 – they could silence the criticism of the jurists. At the same time, they could redirect the destructive energies of a restless jund across the Ifriqiyan–Sicilian channel to secure new sources of manpower and wealth".
Ziyadat Allah's council was divided over the issue, but in the end the exhortations of the respected qadi of Kairouan, Asad ibn al-Furat, who used quotations from the Quran to support his case, swayed them. Asad was placed at the head of the expedition even while retaining his office of qadi, normally incompatible with a military post. The Muslim expeditionary forces are said to have consisted of ten thousand foot soldiers and seven hundred cavalry, mostly Ifriqiyan Arabs and Berbers, but possibly also some Khurasanis. The fleet comprised seventy or a hundred ships, to which were added Euphemius' own vessels.
Initial operations and conquest of Palermo
Muslim landing and siege of Syracuse, 827–828
On 14 June 827, the allied fleets sailed from the Bay of Sousse, and after three days they reached Mazara in southwestern Sicily, where they landed. There they were met with soldiers loyal to Euphemius, but the alliance soon began to show rifts: a Muslim detachment mistook some of Euphemius' partisans for loyalist troops, and a skirmish ensued. Although Euphemius' troops were ordered to place a twig on their helmets as a distinctive mark, Asad announced his intention to wage the campaign without them. Soon after that, Balata, who seems to have taken over the functions, if not the title, of the imperial strategos on the island, appeared nearby with a Byzantine force. The two armies clashed on a plain south-east of Mazara, where Asad's men, after exhortations by their leader, gained a victory. Balata retreated first to Enna and from there to Calabria on the Italian mainland, where he may have hoped to gather more troops. Instead, he died there shortly after his arrival.
Asad then left Mazara under Abu Zaki al-Kinani, and turned to Syracuse: the Muslim army advanced along the southern shore towards the island's capital, but at Qalat al-Qurrat (possibly ancient Acrae), it was met by an embassy from the city which offered tribute if the Muslims halted their advance. The proposal was probably designed to buy time for the city to better prepare itself for a siege, but Asad, either persuaded by the emissaries' assurances or needing to rest his army, halted his advance for a few days. At the same time, Euphemius began to regret his alliance with the Aghlabids, and opened secret contacts with the imperials, urging them to resist the Arabs. The Muslims recommenced their advance soon after, and laid siege to the city. Byzantium, which at the same time was forced to face a threat much closer to home at Crete, was unable to send much aid to the beleaguered island, while the Muslims received reinforcements from Africa. Giustiniano Participazio, the dux of the imperial protectorate of Venice, came to the city's aid, but was not able to raise the siege. The besiegers however suffered from lack of supplies as well as the outbreak of a disease in spring 828, which cost Asad his life. He was replaced by Muhammad ibn Abu'l-Jawari. When a Byzantine fleet arrived, the Arabs raised the siege and tried to sail back to Africa, but were hindered by the Byzantine ships. Thwarted, the Muslim army burned its ships and retreated over land to the castle of Mineo, which surrendered to them after three days.
First siege of Enna and the Byzantine counterattack, 828–829
Despite his contacts with the imperials, Euphemius was now willing to serve as their guide, evidently hoping that the Muslims, humbled by their failure and without the strong will of Asad to guide them, could now be made to serve his purposes. After Mineo surrendered, the Muslim army divided in two: one part took Agrigento in the west, while the other, along with Euphemius, attacked Enna. The garrison of Enna began negotiations, offering to acknowledge Euphemius' authority, but when Euphemius with a small escort met with their emissaries, he was murdered. It is unknown what happened to Euphemius' supporters after his death, whether they dispersed or continued fighting alongside the Muslims.
In spring 829, Michael II sent a new fleet to Sicily under Theodotus, who was well acquainted with the island, having already served as its strategos in the past. After landing, Theodotus marched his army to Enna, where the Arabs were continuing the siege. He was defeated in the subsequent battle, but was able to find refuge in the fortress with most of his men. The Muslims now became so confident of victory that they struck their first coins on the island, in the name of Ziyadat Allah and Muhammad ibn Abu'l-Jawari, who however died a short while after and was replaced by Zubayr ibn Gawth. Shortly after that, Theodotus managed to reverse the situation: he led a sally that routed a Muslim raiding party and then defeated the main Muslim army on the next day, killing 1,000 men and pursuing the rest up to the Muslims' fortified encampment, which he placed under siege. The Muslims tried to break out in a night sortie, but Theodotus was expecting such a move and routed them in an ambush.
The remains of the Muslim army once again sought refuge in Mineo, where Theodotus blockaded them and soon reduced them to the point of eating their horses and even dogs. When they heard of this reversal, the Arab garrison of Agrigento abandoned the city and retreated to Mazara. Thus, by the autumn of 829, Sicily had almost been cleared of the Muslim invaders.