The War of the Straits (Italian: Guerra degli Stretti) or Third Genoese–Venetian War was a conflict fought between the Republic of Venice and the Republic of Genoa, and their allies, in 1350–1355. The third in a series of conflicts between the two major Italian maritime republics, the war resulted from the intense commercial and political rivalry over access to the Aegean Sea and the Black Sea. The main immediate events that precipitated the war were the conflicts over Caffa and Tanais in the northern Black Sea, control of passage through the Bosporus straits—whence the conflict received its name—and the seizure of Chios and Phocaea by the Genoese.
Historical background
In March 1261, the Republic of Genoa and the Byzantine Empire concluded the Treaty of Nymphaeum. The treaty was an offensive alliance against the Republic of Venice, whose naval might alone prevented the Byzantine from completing their long-held ambition to recover Constantinople from the moribund Latin Empire. Genoa, which had recently lost in a colonial conflict against Venice in Acre, was eager for a revanche, and enticed with extensive commercial privileges, including the opening of the Black Sea trade. Founding trade colonies at Caffa (modern Feodosia) and in the Empire of Trebizond, the Genoese soon achieved commercial hegemony in the Black Sea, and control of the northern termini of the great commercial highways leading to inner Asia. Among other reasons, the Black Sea trade was vital for both Genoa and Venice as a source of grain; the burgeoning populations of both cities were reliant on overseas imports.
The two states' commercial rivalry led to the so-called "War of Curzola" in 1296–1299, which ended in the Treaty of Milan without a clear victor: Genoa retained her ascendancy in the Black Sea but was unable to completely exclude the Venetians from it. During the war, the Venetians had operated in the Black Sea, and even sacked the Genoese colony of Pera (Galata), which then lacked fortifications; but Venetian efforts to establish themselves in the region had come relatively late, and eventually led to clashes with the pre-existing Genoese commercial colonies, as happened in Trebizond in 1327–1328 and in Tanais in 1341, before all Italian merchants were expelled in 1343 by the Golden Horde under Khan Jani Beg. The Venetians could count, up to that moment, on a strong commercial presence in the Crimea in the city of Soldaia, which, however, in the first half of the fourteenth century, was struggling to survive due to ruthless competition with the Genoese merchants in Caffa. The Golden Horde's attacks on Caffa from 1344 on caused a brief rapprochement: both states imposed an embargo on the Horde, and Venetians were allowed access to Caffa. In 1346, however, the Venetians negotiated renewed access to Tanais for themselves alone, provoking the ire of the Genoese merchants in Caffa, who engaged in reprisals against their Venetian rivals. The Venetian Senate immediately prohibited its merchants from entering the Black Sea, and declined a Genoese demand to restore access for Venetian merchants to Caffa, provided they stopped trading with Tanais.
Further south, both Genoa and Venice benefited from the decline and enfeeblement of the Byzantine Empire. The Treaty of Nymphaeum resulted in the establishment of a Genoese merchant colony of Pera just across the Golden Horn from the Byzantine capital, Constantinople, which progressively attracted all commerce away from the latter and became a state within a state, independent of Byzantine authority. The Byzantine emperors also awarded the Genoese Zaccaria family the lucrative alum mines of Phocaea, and even joined Genoa in its war against Venice. The Byzantines were not included in the Treaty of Milan, however, and were left to fight against Venice alone, leading to the conclusion of a humiliating treaty in 1302. Seizing the opportunity, the Zaccaria seized the island of Chios in 1304, holding it until reconquered by the Byzantines in 1329.
In 1346, the Genoese armed a fleet funded by private contractors and led by Simone Vignoso. Its aim was ostensibly to assist repel a Golden Horde siege of Caffa, but in reality it was meant to counter possible Venetian moves in the Aegean Sea, where a fleet led by Humbert II of Viennois and supported by Venice was active as part of the Second Smyrniote Crusade. Humbert intended to obtain Chios as a base for the Crusade, but was pre-empted by Vignoso, who attacked and captured the island and Phocaea as well. Both now came under the rule of a joint stock company, the Maona, with the participation of both private contractors and the Genoese state.
This action gave the Genoese strategic bases in the western Aegean to counterbalance the long-established Venetian domains in the south and east, but provoked the ire of both the Venetian doge, Andrea Dandolo, and the Byzantines, although the latter were for the moment embroiled in a debilitating civil war. The subsequent attempts by Emperor John VI Kantakouzenos to shake off Genoese influence and revive the Imperial fleet backfired: in a brief conflict in 1348–1349, the Genoese of Pera captured the newly rebuilt Imperial fleet, blockaded the Byzantine capital, and gave them de facto control over the passage of the Bosporus strait into the Black Sea.
Diplomatic preparations for war
According to the contemporary Byzantine historian Nikephoros Gregoras, the Genoese intended to establish a monopoly on the Black Sea trade, excluding their Venetian rivals entirely from the region. The recent Genoese acquisitions in the Aegean, and their defeat of Kantakouzenos' attempt to curb their power, worried the Venetians, while also pushing the humiliated Byzantine emperor to turn to them for assistance in rolling back the Genoese gains. Some first skirmishes between Venetians and Genoese are recorded as early as 1347/8, after the Venetians returned to Tanais in violation of their previous agreement with the Genoese. Venice was preoccupied for most of the 1340s with its rivalry with Louis I of Hungary over control of Dalmatia, exacerbated by the revolt of Zara (Zadar), the chief Venetian possession in Dalmatia. The conclusion of an eight-year peace with Hungary in August 1348 left Venice free to deal with Genoa. During 1349, the Venetians also worked to secure support from, or at least good relations with, various potentates in northern Italy: Ubertino I da Carrara of Padua, Mastino II della Scala of Verona, Ludovico I Gonzaga of Mantua, and Luchino Visconti of Milan. In September 1349, the Venetian government also concluded a five-year truce with the Byzantines.
By early 1349, the savi agli ordini, Venice's board of naval commissioners, was charged with examining relations with Genoa. A conscription was imposed, and wood began to be gathered for the oncoming conflict. These preparations could not long remain secret, and in April the Doge of Genoa, Giovanni da Murta, sent a letter to Dandolo offering negotiations, and asking the Venetian fleet that was then being prepared for the East to assist the Genoese in case of attack by either the Byzantines or the Turks. It is unclear how sincere or disingenuous this proposal was, but even though it was joined by papal appeal for peace on 24 November 1349, it could not halt the slide to war, as both Venice and Genoa sought only to gain time and complete their preparations. Informal hostilities began in spring 1350, when a Genoese fleet prevented Venetian merchant vessels from reaching Tanais. The Venetians complained to Pope Clement VI, who could only helplessly respond that he would try to ensure that the captured goods would be returned.
The imminent conflict between Genoa and Venice also hampered papal plans for a new crusade to secure Smyrna against the Aydinid Turks; the Venetians were willing to contribute ships to the anti-Turkish league, but in April 1350 they demanded that the Genoese also participate in any such league. In July 1350, the distinguished Venetian statesman Marino Faliero, who had been a member of the naval board and at least one commission examining relations with Genoa, was named ambassador to Genoa, in hopes of averting the imminent conflict. He was recalled after only a few days, leaving only his secretary to continue with the mission, after news—which proved to be false—arrived in Venice that Venetian citizens had been killed by the Genoese in the Black Sea. Faliero was not replaced, making war inevitable.
Course of the war
Initial clashes
On 6 August 1350, Venice declared war on Genoa. On the same day, a compulsory loan to finance the fleet was decreed. Marco Ruzzini was elected Captain General of the Sea, and set sail at the end of August for Greece with 35 galleys. Both cities had suffered heavy losses because of the Black Death—which had come to Europe with ships from Caffa in 1348—that had depleted their citizenry: Genoa lost about 30,000 of its 60,000–70,000 inhabitants, while Venice went from 120,000 in 1338 to about 65,000 in 1351. According to the historian Frederic C. Lane, the remaining male citizen population did not suffice for manning any more than 25 galleys, meaning that the Venetian government had to resort to conscription in Dalmatia and its Greek possessions to fill out its fleet's ranks. In addition, the conscription of the Venetian citizens proved unpopular, and many extricated themselves by hiring substitutes.
The result was that the Venetian fleet was manned by crews that were both inexperienced an indisciplined, a fact that became evident at the first battle of the war: on 17 September, Ruzzini's fleet attacked a Genoese fleet of 14 merchant galleys under Nicola di Magnerri at Castro (Kastri), near the Venetian colony of Negroponte (Euboea). The Venetians captured ten ships, but the inexperience and indiscipline of the conscripted crews, which abandoned the battle to plunder the captured vessels, allowed the remainder to escape to Chios. This provoked outrage at Venice, but the Venetian Senate failed to pursue the matter, realising that many of the crews were attracted by the promise of pay and booty, and were likely to mutiny if they were denied that. Ruzzini then sailed to Pera, where he conducted a brief and unsuccessful siege, before conducting a foray into the Black Sea. On his return home, he was welcomed with honours. In the meantime, however, the four galleys he had allowed to escape joined with five more Genoese ships at Chios, and, under the command of Filippo Doria, they launched a successful surprise attack on the city of Negroponte (Chalkis) in October, and burned its harbour, though the citadel resisted successfully. The local Venetian bailo (governor), Tommaso Viadro, fled the field, and was later put on trial for cowardice in Venice; he only escaped execution due to the intervention of the Doge. Neither Viadro nor Ruzzini were selected again for military commands.
Venetian alliances and Genoese reaction
In spring 1351, a papal appeal to the two combatants to cease the conflict had no effect, as did a letter by the celebrated poet Petrarch to the Doge of Venice, enjoining the two states "to lay down their uncivilized weapons, to unite their souls and their flags and to give each other the kiss of peace". Instead, the conflict expanded across the Mediterranean. The first actions of the war had demonstrated to Venice the need for much larger forces, and thus the need for allies, to make up for its own diminished human resources. As a result, Venice turned to two of Genoa's rivals: the Byzantines and the Crown of Aragon. An attempt to secure the support of another Italian naval power, the Republic of Pisa, was rebuffed. The Aragonese had been at loggerheads with the Genoese over Sardinia, and despite previous confrontations with the Venetians over the activities of the Catalan rulers of the Duchy of Athens in Greece, King Peter IV of Aragon and his influential commander, Bernat II de Cabrera, proved willing to enter into an alliance with Venice. The treaty, concluded at Perpignan on 16 January 1351, was scheduled to last at first until 29 September, after which it would be renewed for four years. Neither party was to sign a separate peace. Aragon undertook to equip a fleet of 18 galleys for operations in the Tyrrhenian Sea against a monthly payment of 12,000 florins, two thirds of which was to be paid by Venice, in exchange for one third of all spoils. A further 12 Aragonese galleys were to be rented by Venice.