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This chapter is an updated synthesis of the geology of bedrocks recovered from the seafloor and drillings in the Tyrrhenian Sea. Several decades of sampling indicate that the foundation of this back-arc basin consists of late Miocene to Recent igneous rocks plus oceanic crust (accompanying basin extension) and of rocks passively affected by rifting since Tortonian times. The rifted continental substrate connects Sardinia and Corsica (Alpine chain and its European foreland) to peninsular Italy and Sicily (Apenninic--Maghrebian chain and Calabria terrane). The types and distribution of recovered bedrock samples compared to geology of emerged areas indicate that the Mesozoic Tethyan Ocean was limited to the south by a line connecting the Orosei Canyon (to the west) with northern Calabria (to the east). South of that limit, only Apenninic, Oligocene to Recent compressive deformations with Apulian-African vergence occurred prior to the onset of Tyrrhenian stretching. It turns out that the Cretaceous-Paleogene, Europe-verging Alpine chain did not develop all around Sardinia or further west of it. The chain units deformed until Middle Miocene in the Calabria terrane appear strongly dispersed throughout the extremely thinned southern basin, and were probably the domains most affected by stretching. In the southern Tyrrhenian area, the igneous rocks coeval to extension form two different groups as regards location and magma character. From Sardinia to the extremely thinned central Vavilov Plain, Pliocene-Quaternary volcanism is largely of ocean island basalt (plus subordinated MORB) type, while Pliocene arc-type magmas are very minor. Ages of volcanic occurrences are rather casually distributed across this wide area. In the southeastern basin, comprising the extremely thinned Marsili Plain and the Eolian Islands (separated from the central Vavilov Plain by a thicker crustal sector), volcanism is instead only of arc-type and is essentially of Pleistocene to Recent age. Taking into account the history of compressive deformation in the southern Apennines, coeval to extension in the southern Tyrrhenian Basin, the age--space distribution of different magma types may be linked to the different characters of the Ionian lithosphere (thinned continental versus oceanic) subducting at different times. [ABSTRACT FROM AUTHOR]

In the later Middle Ages the Muslim states of North Africa had by and large been fairly pacific. Although there had always been a certain number of corsairs amongst their populations, they were certainly not renowned for their bellicosity and for their prosecution of jihād against the Christian infidel at sea. Indeed, in the fourteenth and fifteenth centuries it had been Christian, and particularly Catalan, corsairs who had been the major threat to maritime traffic in the western Mediterranean. According to Ibn Khaldūn, Maghrebin pirates and corsairs first assumed serious dimensions around 1360 at Bougie. By 1390 corsairs operating from Tunisia had become a severe enough menace to Christian shipping to provoke Genoa to organize a Crusade against Mahdia. Native Maghrebins and Moorish exiles from Spain were always to remain active as corsairs in North Africa throughout the fifteenth and sixteenth centuries, but it was Ottoman corsairs under Kemāl Reis, moving to the Maghreb around 1487, who ushered in the great days of the Barbary corsairs. The move to the Maghreb was a logical extension of the Ottoman push westwards to the shores of the Ionian; however, as we shall see, it was not to offer the Barbary corsairs the same logistical advantages that the push to the west coasts of the Balkans did the Ottomans. [ABSTRACT FROM AUTHOR]

At the same time as the fleets of Pisa, Genoa, Venice, and other maritime powers of the Christian West were confronting the navies of the Fatimids and Ayyubids in the waters of the Levant, a far wider confrontation at sea was beginning all over the Mediterranean; a confrontation whose outcome was to have infinitely greater importance in the long term than the wars of the Crusades. In the eleventh century there commenced a decisive movement by the merchant marine of the Christian West to establish its dominance over those of Byzantium and Islam in Mediterranean maritime shipping and commerce. In fact, of course, and particularly because of the key role played by the guerre de course in both, the essentially naval and strategic struggle between the three civilizations on the one hand and the competition in maritime traffic on the other were integrally connected and part and parcel of the same historical phenomenon. Because of its complex and multiplex nature, the parameters and evolution of this competition in maritime traffic between the merchant marines of the three civilizations are even now obscure, despite an enormous historical scholarship devoted to the subject over the past century. The rich European archives have been ransacked to document what was beyond a shadow of doubt an enormous growth of shipping and maritime commerce in Western seaports such as Genoa, Pisa, Venice, Marseilles, Barcelona, Montpellier, and Dubrovnik. [ABSTRACT FROM AUTHOR]

When he was still as yet only governor of Syria, the first of the Umayyad caliphs, Mu'āwiyyah, launched the initial Muslim challenge to Byzantine maritime domination of the Mediterranean with a raid on Cyprus in AD 649, just seventeen years after the death of Muhammad. Soon afterwards, in 655, the Muslims won their first great naval victory over the Byzantines off Phoenix, near Chelidonia in Lycia. From then on Islam was to challenge Christendom at sea in the Mediterranean for a thousand years. In the early Middle Ages, pace the great naval assaults on Constantinople itself in 673-9 and 717 18, the most serious threat from Islam developed in the ninth and tenth centuries. During that period Muslims were able in some cases to capture and hold, and in other cases to compromise seriously Christian authority over, all of the islands and some of the important mainland regions and bases along the trunk routes of the sea. Cyprus saw a shared condominium of power between the Abbasid Caliphate and Byzantium (figure 26). Muslim fleets, ghazi squadrons, and corsair ships operated from Umayyad Spain, Aghlabid Tunisia, the Balearics, Sicily, Bari, Taranto, Monte Garigliano, Fraxinetum, Crete, Tarsus and Tripoli in Syria, and to some degree from Corsica, Sardinia, Rhodes, and Cyprus. Their operations took the form of corsair cruises by single ships or small flotillas, raids on coasts and islands for booty and slaves by ghazi squadrons pursuing the ghazw of jihād, and full-scale invasions by large fleets. [ABSTRACT FROM AUTHOR]

For ancient and medieval man, the Mediterranean had a deserved reputation for benevolence. Compared to the Atlantic and the North Sea, it offers favourable conditions for navigation for many more months of the year. Clear skies, moderate winds, and slight seas can be expected across most of the sea from late March through to late October. Because of the small size of the sea, in world geographical and meteorological terms, the huge rollers which make Atlantic navigation so dangerous in storms are not to be found in the Mediterranean; although it is true that the short, steep chop raised by strong winds in some parts of the Mediterranean can be equally as hazardous as the Atlantic's rollers. Similarly, the tides, which so governed navigation in the North Sea as to affect the evolution of ship design, are virtually absent from the Mediterranean except in certain narrows. The many islands scattered throughout the northern half of the sea reduced the need to make long voyages out of sight of land and thus promoted maritime traffic in an age of small ships. The clear skies of summer nights facilitated navigation by the stars. But if the Mediterranean was particularly favourable to men's endeavours upon the sea by comparison to other waters, nevertheless geographical and meteorological factors still influenced profoundly matters such as ship design, the rhythms of seasonal voyaging, and the choice of routes. [ABSTRACT FROM AUTHOR]

Ibn Jubayr, a twelfth-century Muslim pilgrim and traveller from Andalusia, left Acre on 18 October 1184 on a Genoese ship bound for Messina. Of his departure he wrote that: Our stay there [at Acre] was prolonged twelve days, through the failure of the wind to rise. The blowing of the winds in these parts has a singular secret. It is that the east wind does not blow except in spring and autumn, and, save at those seasons, no voyages can be made and merchants will not bring their goods to Acre. The spring voyages begin in the middle of April, when the east wind blows until the end of May … The autumn voyages are from the middle of October, when the east wind (again) sets in motion … it blows for (only) fifteen days, more or less. There is no other suitable time, for the winds then vary, that from the west prevailing… at daybreak of … the 18th of October the ship set sail… Steadily, we sailed on, under a propitious wind of varying force, for five days. Then the west wind came out of ambuscade and blew into the ship's bows. […] [ABSTRACT FROM AUTHOR]