the medieval mediterranean 81
Mediterranean. To rule the seas, possession of a fleet capable of securing the coastlines
and launching attacks against foreign territories or enemy ships was a political neces-
sity; however, beside these official fleets, expensive to build and maintain, private ves-
sels, more or less closely controlled by the power, could also contribute. Above all,
dominating shipping routes required the control of crossing points: straits (and to
some extent isthmuses) and islands. In this respect, changes of rule over islands cor-
responded to changes in the control of sea routes, thus providing criteria for periodiz-
ing the political history of the medieval Mediterranean.
Contrary to a still widespread idea (Planhol, 2000), Muslim authorities quickly
developed a maritime policy in the Mediterranean. Of course, none of the new capi-
tals (Damascus or, especially, Baghdad) or important cities (Fustat/Cairo, Kairouan
or Cordoba) were located on the coast. But if rulers avoided the shore, still threatened
by the Byzantines, ports such as Alexandria, Tyre or Sousse were often reused, taking
advantage of the shipbuilding or navigation knowledge of coastal populations. The
Muslim fleet, first constituted in order to conquer the rival capital of Constantinople,
was powerful enough to inflict a crushing defeat on the Byzantines at the “Battle
of the Masts” in 655. Once the Umayyad caliphs gave up on the conquest of
Constantinople, they reorganized the fleet to serve their policy of dominating the
Mediterranean, enabling raids along Christian shores and especially against the islands.
In the ninth century Muslim domination was consolidated by the conquest of Sicily
and Crete, and naval policy became an important issue for the two new caliphates, the
Fatimid and the Umayyad of Cordoba, which made jihad at sea a major source of
legitimacy. At the end of the tenth century the Mediterranean was divided into two
areas of domination: a Byzantine Mediterranean, now limited to the eastern basin
(where the emperors were able to retake Cyprus and Crete) and the Black Sea; and
the rest of the sea, dominated by Muslims (Picard, 2013) despite the resistance of
Frankish (especially Venetian) fleets in the western Mediterranean. The maritime
frontier dividing these two areas gradually moved northward to Christian shores when
the Muslims succeeded in conquering the islands.
Within a few decades, the political and economic development of western Europe
disrupted that balance. In 1096–1099, the armies of the First Crusade took an over-
land route to Palestine. As early as 1099, however, Genoese and Pisan fleets helped
conquer the coastal towns; henceforth, these fleets, mainly Italian, remained indispen-
sable to the survival of the Latin states in Syria, bringing food, money, men and weap-
ons from Europe. The Crusades have sometimes been seen as the main cause of the
shift of domination in the Mediterranean, and of the military and economic triumph
of the western Christians. This is not entirely false: Muslim fleets suffered from
Christian expeditions in the western as well as the eastern Mediterranean. But it
should be noted, first, that Italian naval power was already considerable before the
Crusades, and, second, that the defeats the Christians suffered in Syria in the twelfth
and thirteenth centuries did not cause a decline in their naval domination of the
Mediterranean. There was thus a deeper and more lasting evolution, characterized by
a displacement of domination from east to west and from south to north. From the
tenth century, navigation really developed in southern Europe (where it had probably
never been completely abandoned), first in ports in areas formerly under Byzantine
rule and maintaining relations with Constantinople (southern Italy, Sicily, and Venice),
then in the northern Tyrrhenian. In an initial stage, these Italian fleets aimed primarily