of the
Theodosian Walls of Constantinople In 674, the Arab fleet sailed from its bases in the eastern Aegean and entered the Sea of Marmara. According to the account of Theophanes, they landed on the
Thracian shore near
Hebdomon in April, and until September were engaged in constant clashes with the Byzantine troops. As the Byzantine chronicler reports, "Every day there was a military engagement from morning until evening, between the outworks of the
Golden Gate and the
Kyklobion, with thrust and counter-thrust". Then the Arabs departed and made for Cyzicus, which they captured and converted into a fortified camp to spend the winter. This set the pattern that continued throughout the siege: each spring, the Arabs crossed the Marmara and assaulted Constantinople, withdrawing to Cyzicus for the winter. In fact, the "siege" of Constantinople was a series of engagements around the city, which may even be stretched to include Yazid's 669 attack. Both Byzantine and Arab chroniclers record the siege as lasting for seven years instead of five. This can be reconciled either by including the opening campaigns of 672–673, or by counting the years until the final withdrawal of the Arab troops from their forward bases, in 680. , from the
Madrid Skylitzes. It was used for the first time during the first Arab siege of Constantinople, in 677 or 678. The details of the clashes around Constantinople are unclear, as Theophanes condenses the siege in his account of the first year, and the Arab chroniclers do not mention the siege at all but merely provide the names of leaders of unspecified expeditions into Byzantine territory. Thus from the Arab sources it is only known that Abdallah ibn Qays and Fadhala ibn 'Ubayd raided Crete and wintered there in 675, while in the same year Malik ibn Abdallah led a raid into Asia Minor. The Arab historians
Ibn Wadih and
al-Tabari report that Yazid was dispatched by Mu'awiya with reinforcements to Constantinople in 676, and record that Abdallah ibn Qays led a campaign in 677, the target of which is unknown. At the same time, the preoccupation with the Arab threat had reduced Byzantium's ability to respond to threats elsewhere: in Italy, the
Lombards used the opportunity to conquer most of
Calabria, including
Tarentum and
Brundisium, while in the Balkans, a coalition of Slavic tribes
attacked the city of
Thessalonica and launched seaborne raids in the Aegean, even penetrating into the Sea of Marmara. Finally, in late 677 or early 678 Constantine IV resolved to confront the Arab besiegers in a head-on engagement. His fleet, equipped with Greek fire, routed the Arab fleet. It is probable that the death of admiral Yazid ibn Shagara, reported by Arab chroniclers for 677/678, is related to this defeat. At about the same time, the Muslim army in Asia Minor, under the command of
Sufyan ibn 'Awf, was defeated by the Byzantine army under the generals Phloros, Petron and Cyprian, losing 30,000 men according to Theophanes. These defeats forced the Arabs to abandon the siege in 678. On its way back to Syria, the Arab fleet was almost annihilated in a storm off
Syllaion. The essential outline of Theophanes' account may be corroborated by the only near-contemporary Byzantine reference to the siege, a celebratory poem by the otherwise unknown Theodosius Grammaticus, which was earlier believed to refer to the second Arab siege of 717–718. Theodosius' poem commemorates a decisive naval victory before the walls of the city—with the detail that the Arab fleet too possessed fire-throwing ships—and makes a reference to "the fear of their returning shadows", which may be interpreted as confirming the recurring Arab attacks each spring from their base in Cyzicus. ==Importance and aftermath==