The trajectory of naval warfare in the Mediterranean had some similarities with that in the north: a power vacuum at the start of our period, in which new contenders arose and disputed mastery of the sea. By C.1100 the naval war against Islam had already been won by Christians. Westerners were masters of Corsica, Sardinia, Sicily, southern Italy, and the coasts of Palestine and Syria. The difficulty of dominating the Mediterranean from its eastern end had also affected Byzantine sea power. Byzantium was already in the process of being reduced to minor importance as a naval power by comparison with some rivals further west.
The Egyptian Fatimid fleet, which had once been a formidable force is almost unmentioned in the records after the first decade of the 1100s: it continued to exist, and could put up to seventy galleys at sea in the mid-twelfth century, but it became confined to a largely defensive role. By 1110, the crusaders held almost all the Levantine ports; thereafter, the operation of Egyptian galleys against Christian shipping was practically limited to home coasts: they had virtually no friendly ports to the north in which to water. Turkish naval power, which would be invincible by the end of our period, had hardly been foreshadowed. In the 1090s Syrian collaborators provided free-lance Seljuk war-chiefs with ships that briefly seized Lesbos and Chios and even threatened Constantinople; but the crusades forced the Seljuks back; the coasts were not recovered for Islam for another hundred years or so. The crusader states depended on long and apparently vulnerable communications by sea along lanes that led back to the central and western Mediterranean. Yet they were hardly jeopardized by seaborne counter-attack. Saladin created a navy of sixty galleys almost from nothing in the 1170s, but he used it conservatively and with patchy success until it was captured almost in its entirety by the fleet of the Third Crusade at Acre in 1191.
The Christian reconquest of the Mediterranean had been effected, in part, by collaboration among Christian powers. Venetian, Pisan, Genoese, and Byzantine ships acted together to establish and supply the crusader states of the Levant in their early years. Successful allies, however, usually fall out. Relative security from credal enemies left the victors free to fight among themselves. The twelfth century was an era of open competition in the Mediterranean for the control of trade, by means which included violence, between powers in uneasy equipoise. In the twelfth century, Sicily was perhaps the strongest of them. It maintained the only permanent navy west of the twenty-second meridian, but the extinction of its Norman dynasty in 1194 marked the end of its potential for maritime empire. Pisa was a major naval power of the twelfth and thirteenth centuries: its war against Amalfi in 1135-7 effectively dashed all prospect of that port emerging as an imperial metropolis; and the contribution of its ships, with those of Genoa, was decisive in the destruction of the Norman Kingdom of Sicily; but Pisa made a poor choice of allies in thirteenth-century wars and, after a series of setbacks which left it isolated, at the battle of Meloria in 1284 it suffered a blow at Genoese hands from which its navy never recovered. So many prisoners were taken that 'to see Pisans', it was said, 'you must go to Genoa.'
Three rivals stood the course of these wars: the Genoese and Venetian republics and the House of Barcelona. At different times and in overlapping areas of the Mediterranean, all three established seaborne 'empires'-zones of preponderance or control over favoured routes and coasts. The possibilities were demonstrated in 1204, when Constantinople fell to a mixed host of Westerners and Venice carved a maritime empire out of the spoils. The Republic became mistress of 'one quarter and one half of a quarter' of Byzantine territory. At first, Genoa responded with energetic corsair warfare, which had effectively failed when the peace settlement of 1218 nominally restored to Genoese merchants the right to live and trade in Constantinople. In practice, however, they remained victims of the Venetian hegemony until 1261, when Byzantine irredentists recaptured Constantinople and the uneasy parity of the Genoese and Venetian traders was restored.
Genoa acquired an empire of its own-albeit one much less tightly centralized than that of Venice: it comprised, at first, an autonomous merchant quarter in Constantinople and scattered settlements along the northern shore of the Black Sea, ruled by a representative of the Genoese government. By Byzantine grants of 1267 and 1304, the alum-producing island of Chios became the fief of a Genoese family. Around the middle of the fourteenth century its status was transformed by the intrusion of direct rule from Genoa. The Aegean was effectively divided between Genoese and Venetian spheres. Venice dominated the route to Constantinople via the Dalmatian coast and the Ionian Islands, whereas Genoa controlled an alternative route by way of Chios and the eastern shore.
Eastern Mediterranean rivalry between Genoa and Venice was paralleled in some ways in the western rivalry between Genoa and the dominions of the House of Barcelona. Catalans were relative latecomers to the arena. They enjoyed privileged natural access to the entire strategic springboard of the western Mediterranean-the island bases, the Maghribi ports; but while the islands were in the unfriendly hands of Muslim emirs, they were trapped by the anti-clockwise flow of the coastal currents. But by 1229 the power of the count-kings of Barcelona and Aragon and the wealth of their merchant subjects had developed to the point where they could raise enough ships and a large enough host to attempt conquest. By representing the venture as a holy war, Jaume I was able to induce the landlubber aristocracy of Aragon to take part in the campaign. Once Majorca was in his hands, Ibiza and Formentera fell with relative ease. The island-empire was extended in the 1280s and 129os, when Minorca and Sicily were conquered. In the 1320s an aggressive imperial policy reduced parts of Sardinia to precarious obedience.
Meanwhile, vassals of members of the House of Barcelona made conquests even further east, in Jarbah, Qarqanah, and parts of mainland Greece. The impression of a growing maritime empire, reaching out towards the east-perhaps to the Holy Land, perhaps to the spice trade, perhaps both was reinforced by the propaganda of count-kings who represented themselves as crusaders. The easterly vassal-states were, however, only nominally Catalan in character and, for most of the time, tenuously linked by juridical ties with the other dominions of the House of Barcelona. Catalan naval operations in the eastern Mediterranean were made in alliance with Venice or Genoa and were generally determined by western Mediterranean strategic considerations. If the island-conquests of the House of Barcelona stretched eastward, towards the lands of saints and spices, they also strewed the way south, towards the Maghrib, the land of gold. They were strategic points d'appui of economic warfare across the African trade routes of other trading states. From 1271 onwards, at intervals over a period of about a century, the naval strength of the count-kings was used in part to exact a series of favourable commercial treaties governing access to the major ports from Ceuta to Tunis.
Of the well integrated Catalan world, the easternmost part, from the 1280s, was Sicily. For the count-king Pere II its conquest was a chivalresque adventure in dynastic self-aggrandisement; for his merchant-subjects, it was the key to a well-stocked granary, a way-station to the eastern Mediterranean and, above all, a screen for the lucrative Barbary trade, which terminated in Maghribi ports. Normally ruled by a cadet-line of the House of Barcelona, the island was vaunted as 'the head and protectress of all the Catalans', a vital part of the outworks of Catalonia's medieval trade. Had Sardinia become fully part of the Catalan system the western Mediterranean would have been a 'Catalan lake'. But indigenous resistance, prolonged for over a century, forced repeated concessions to Genoa and Pisa. The Catalans paid heavily for what was, in effect, a political and commercial condominium. By a cheaper policy-without acquiring sovereign conquests further afield than Corsica-Genoa ended with a greater share of western Mediterranean trade than her Catalan rivals.
Thus, between them, Venice, Genoa, and a Spanish state established a sort of armed equilibrium-a surface tension which covered the Mediterranean. It was broken at the end of our period by the eruption of a new maritime power. The Turkish vocation for the sea did not spring suddenly and fully armed into existence. From the early fourteenth century, pirate-nests on the Levantine shores of the Mediterranean were run by Turkish chieftains, some of whom allegedly had fleets of hundreds of vessels at their command. The greater the extent of coastline conquered by their land forces, as Ottoman imperialism stole west, the greater the opportunities for Turkish-operated corsairs to stay at sea, with access to watering-stations and supplies from on shore. Throughout the fourteenth century, however, these were unambitious enterprises, limited to small ships and hit-and-run tactics.
From the 1390s, the Ottoman sultan Bayezid I began to build up a permanent fleet of his own, but without embracing a radically different strategy from the independent operators who preceded him. Set-piece battles usually occurred in spite of Turkish intentions and resulted in Turkish defeats. As late as 1466, a Venetian merchant in Constantinople claimed that for a successful engagement Turkish ships needed to outnumber Venetians by four or five to one. By that date, however, Ottoman investment in naval strength was probably higher than that of any Christian state. The far-seeing sultans, Mehmed I and Bayezid II, realized that the momentum of their conquests by land had to be supported-if it were to continue-by power at sea. After the long generations of experiment without success in set-piece battles, Bayezid's navy humiliated that of Venice in the war of 1499-1503. Never, since Romans reluctantly took to the sea against Carthage, had a naval vocation been so successfully embraced by so unlikely a power. The balance of naval strength between Christendom and Islam, as it had lasted for four hundred years, was reversed, at least in the eastern Mediterranean, and a new era can properly be said to have begun.