Very soon after their conquest of the Levant and Egypt, the nascent Caliphate built its own fleet, and in the Battle of the Masts in 655 shattered Byzantine naval supremacy, beginning a centuries-long series of conflicts over the control of the Mediterranean waterways.

[9][10] The Fatimid dynasty claimed descent from Fatima, the daughter of Muhammad and wife of Ali, through Isma'il, the son of the last commonly accepted Shi'a Imam, Ja'far al-Sadiq.

[12] Whatever their true origin, the Fatimids were the leaders of the Isma'ili sect of Shi'ism, and they headed a movement which, in the words of the historian Marius Canard, "was at the same time political and religious, philosophical and social, and whose adherents expected the appearance of a Mahdi descended from the Prophet through Ali and Fatima".

Their missionary activity in the area, begun by Abu Abdallah al-Shi'i in 893, bore fruit swiftly, and in 909, they overthrew the reigning Aghlabid dynasty, allowing the Fatimid leader to come out of hiding and declare himself imam and caliph as al-Mahdi Billah (r. 909–934).

However, in the words of the historian Yaacov Lev, "the enmity between the Fatimids and the Spanish Umayyads took the form of propaganda, subversion and war by proxy" rather than direct conflict, which occurred only once in the two states' history.

[36] Later historians like Ibn Khaldun and al-Maqrizi attribute to al-Mahdi and his successors the construction of vast fleets numbering 600 or even 900 ships, but this is obviously an exaggeration and reflects more the impression subsequent generations retained of Fatimid sea-power than actual reality during the 10th century.

[45][46][47] Although a peace agreement in exchange for annual tribute had been concluded the previous year,[48] in 918, the Fatimids conducted their first attack on the Byzantines, capturing Rhegion on the southern tip of Calabria.

In 922/3, an expedition of 20 ships under Mas'ud al-Fati took the fortress of St. Agatha near Rhegion, while in spring 925 a large army under Ja'far ibn Ubayd, which had been ferried over to Sicily the previous year, raided Bruzzano near Reggio, before sailing on to sack Oria in Apulia.

Informed of the negotiations after capturing a ship carrying the returning Bulgarian and Arab envoys to Simeon, the Byzantines hastened to renew the 917 peace agreement, including the payment of tribute.

[59] In the meantime, another uprising against Fatimid rule erupted in Sicily, as the local governor was judged to be to weak towards the Byzantines, allowing the latter to stop paying the agreed-upon tribute in exchange for the truce.

Al-Mu'izz wrote to the Byzantine emperor, Romanos II, threatening to retaliate if the expedition was not recalled, and urged the ruler of Egypt, Abu al-Misk Kafur, to combine their navies at Barqa in May 961 and initiate joint action.

[73][74] While the Byzantines were concentrating their energies in the east, by 958, the Fatimid general Jawhar al-Siqilli had completed his conquest of North Africa in the name of al-Mu'izz, reaching the shores of the Atlantic Ocean.

The Byzantine attempt to relieve Rometta was heavily defeated, however, and the Fatimid governor Ahmad ibn al-Hasan al-Kalbi destroyed the invasion fleet at the Battle of the Straits early in 965, using divers equipped with incendiary devices filled with Greek fire.

[90] This was followed by the conclusion of a ten-year truce in 999/1000 that, despite the continuing rivalry over Aleppo and occasional rifts, was repeatedly renewed and ushered a period of peaceful and even friendly relations that lasted for decades,[91][92] only interrupted by brief war over Laodicea sometime between 1055 and 1058.

[104] As the naval historian John H. Pryor points out, at an age where even the Italian maritime republics assembled their fleets on an ad hoc basis, Fatimid Egypt was one of only three states in the Mediterranean or the rest of Europe—along with Byzantium and the Norman Kingdom of Sicily—to maintain a standing navy.

According to Hamblin, it took on the average two months from the onset of a siege against one of the coastal cities until the Fatimids were informed, mobilized their navy and army, and the latter arrived at Ascalon ready for action.

[112] The Fatimid navy remained in existence until it was destroyed at its arsenal in November 1168, when the vizier Shawar set fire to Fustat to prevent its fall to the Crusaders under Amalric of Jerusalem.

[115] Likewise, on the Palestinian and Syrian coasts the local port cities were important maritime centres,[119] but information on the extent of Fatimid naval presence or the operation of arsenals there is virtually non-existent.

[120] According to the early 15th-century writer Ahmad al-Qalqashandi, the Fatimids also maintained three to five ships in the Red Sea to protect commerce and the pilgrim traffic, with Suez and Aydhab as their bases.

[121][122] This does not appear to be corroborated from contemporary sources, however, and as Yaacov Lev points out, "considering the length of the Red Sea and the limited range of the galleys, the presence of such a small squadron had little practical meaning."

[121] On the other hand, during the conflicts with the Byzantines in the late 10th century, the sources do not report any permanent presence of Fatimid ships in the Levantine ports, suggesting that it operated solely from Egypt.

The total manpower reached some 5,000 men, divided into a system of naval ranks analogous to that of the army, with pay scales of two, five, ten, fifteen, and twenty gold dinars a month.

[131][132] Under the direction of the vizier Isa ibn Nestorius, work began anew, with wood stripped from the capital's buildings; even the huge doors of the mint were removed.

[131] A naval raid shortly after, in summer 996, returned with 220 prisoners, but a fleet of 24 ships sent to the aid of Manjutakin's troops, who were besieging Antartus, was lost when it was wrecked on offshore cliffs in bad weather.

Once again, however, the co-operation between fleet and army broke down; after waiting for twenty days off Jaffa, and repeated requests to Ascalon for assistance went unanswered, the Fatimid admiral Ibn Qadus retreated.

[143][106] The Fatimids again launched an attack on Jaffa in 1105, but the fleet left for Tyre and Sidon after the land army was defeated, and was caught up in a storm that washed 25 ships ashore and sunk others.

19 Fatimid ships manage to break through to Beirut, defeating and capturing some of the Christian vessels blockading it, but the arrival of a Genoese fleet bottled them up inside the harbour, forcing their crews to fight alongside the inhabitants on the ramparts until the city fell.

The presence of this strong fleet, the losses suffered at Beirut, as well as the lateness of the season and the risks of sailing in winter, forced the Fatimid navy, although anchored at nearby Tyre, not try to assist the beleaguered city, which fell on 4 December.

[143][146] Not only that, but due to the inability of the Fatimids to provide a naval escort, many Muslim merchant ships were captured by Christian warships off the Egyptian coast at Tanis and Damietta in the same summer.

[158] When the Crusaders under King Amalric of Jerusalem captured Bilbays, a fleet of 20 galleys and 10 harraqat (ships equipped with Greek fire) is mentioned as operating on the Nile.