The Scaliger War was a conflict fought in 1336–1339 between the Scaliger lords of Verona, Mastino II della Scala and Alberto II della Scala, who had built an extensive territorial state in northern Italy, and a coalition of powers threatened by Scaliger expansion. These were chiefly the Republic of Venice, antagonized by the imposition of taxes on overland trade and the Scaligers' threat to end Venetian salt monopoly, and the Republic of Florence, which resented the Scaliger annexation of Lucca, that Florence had claimed for itself. After the first victories of the anti-Scaliger coalition, it was joined by Milan, Mantua, and Ferrara, who all had reasons to fear Scaliger ambitions. The turning point of the war was the end of Scaliger dominion over Padua in 1337, which became a separate, Venetian-influenced lordship under Marsilio da Carrara. The peace treaty, concluded at Venice on 24 January 1339, deprived Mastino II of most of his recent gains, reducing Scaliger domains to Verona and Vicenza, as well as Lucca and Parma, which were soon lost. The annexation of Mestre and Treviso to Venice marked the beginnings of the Venetian mainland state.
Background
In the second half of the 13th century, the Scaliger family had seized control of Verona and converted it from a commune into a hereditary lordship. During the reign of Alboino I (1301–1311) and his brother Cangrande I (1308–1329), the Scaligers entered into an alliance with the Holy Roman Emperor Henry VII, supporting the pro-Imperial and anti-Papal Ghibelline faction in northern Italy; in exchange, in March 1311 the Scaligers were named Imperial vicars of Verona and its territory, lending their rule Imperial legitimacy. At the same time, Veronese troops helped the Imperials capture Vicenza, which until then had belonged to Padua, one of the chief cities of the pro-Papal and anti-Imperial Guelph faction. The following years were marked by Cangrande's ambition to capture Padua as well.
This began a long period of fighting, broken by short-lived armistices, between Padua and Verona, each in turn seeking regional allies. The Republic of Venice, Emperor Louis the Bavarian and the Habsburg Dukes of Austria intervened at different times in the conflict. For a while, Padua voluntarily submitted to the rule of German vicars appointed by the Habsburgs to protect the city from being captured by the Scaligers, while among Cangrande's staunchest confederates were the Ghibellines exiled from Padua. Taking advantage of internal rivalries in these cities, Cangrande seized Feltre in June 1321 and Belluno in October 1322. After ten years of conflict, Padua's resistance also began to falter: riven by civil strife, growing resentful of the German mercenaries in their midst, and hard-pressed in the field, the city held out until September 1328, when Marsilio da Carrara, newly elected as lord of Padua, submitted to Cangrande and agreed to rule on his behalf, cemented by a marriage alliance between Cangrande's nephew, Mastino II, and Taddea da Carrara, daughter of Jacopo I da Carrara, who had ruled as Lord of Padua in 1318–1320. In July 1329, Cangrande added Treviso to his domains, but died there five days later.
Cangrande was succeeded by his nephews, the sons of Alboino: Mastino II and Alberto II, although the latter was clearly overshadowed by Mastino in authority. In August 1329, Alberto moved his residence to Padua, and built his own palace in the city. Marsilio da Carrara was dismissed from office, and instead demoted to serving the growing Scaliger territorial state as a soldier and administrator. Mastino continued Cangrande's policy of expansion: despite the opposition of Henry VII's son, John of Bohemia, in 1332, the Scaligers captured Brescia, followed in 1335 by Reggio Emilia, Parma, and Lucca. The Scaliger domains thus reached their greatest extent, with some modern historians arguing that the Scaligers' ultimate aim was the creation of a supra-regional state with common institutions, while others cite the continued autonomy of individual cities, as well as the diverging interests and initiatives of local Scaliger lieutenants, as evidence arguing against a centralizing project of this kind.
Friction with Venice
Scaliger expansion had until then been tolerated by the Republic of Venice; as late as 1329, the Republic had awarded Venetian citizenship to Cangrande and his successors, and relations appear to have been amicable during the first half of the 1330s. A first point of friction was the demand in 1332 that Venetian citizens and monasteries should pay taxes for their possessions in Scaliger territories. This was followed in 1335 by the installation of a chain across the Po River at Ostiglia that enforced taxes on river traffic. This caused concern in Venice, as Venice was dependent on free commerce through the Po valley, and reliant on the import of grain from the mainland territories under Scaliger control. Traditional historiography, influenced by the pro-Venetian point of view of the main source for the conflict, the chronicle of Jacopo Piacentino, expresses the view that these events represented deliberate Scaliger provocations. Correspondingly, the traditional thesis is that Venice was dragged into a land war unwillingly, this sort of conflict being foreign to the maritime-minded republic with its traditional reluctance to get involved in mainland Italian affairs. Modern historians acknowledge the reluctance of the Venetian patriciate to engage in an open conflict; not least Doge Francesco Dandolo is recorded to have been fiercely opposed to the war. Nevertheless they also affirm that the road to it was actively shaped by Venetian initiatives, at least after 1335, when the Scaliger annexation of Parma and Brescello put control of the Po basin in their hands and threatened to constrain the hitherto unfettered Venetian access to it.
In September 1335, Venice sent a first embassy to Verona to lodge complaints about the new Scaliger measures, but the Scaligers did not respond until January 1336. At that time, the Republic sent an ultimatum demanding the reversal of these measures, but without success. In March Venice sent a final embassy to the Scaliger lords; to back up the embassy with actions, the Venetian Senate halted the export of salt from the salt pans of the Venetian Lagoon to Scaliger territories, soon extended to a full embargo of foodstuffs. Negotiations in April 1336, mediated by Marsilio da Carrara and the lord of Milan, Azzo Visconti, came close to resolving the issue, as the Scaligers agreed to remove the barrier at Ostiglia and Venice to restore the salt supply; but suddenly Venice hardened its position, and on 14 May 1336, the Venetian Senate reaffirmed its demands, seeking full victory. In response, the Scaligers began creating salt works of their own at Petadebò near Chioggia, where the Paduans had already attempted it in 1304, leading to a brief conflict with Venice. The works protected by troops and a newly constructed castle, the Castello delle Saline (lit. 'Castle of the Saltworks'). At the same time the Republic of Florence, which had coveted Lucca for itself, also began moving against Scaliger interests, by persuading its fellow Guelph city, Bologna, to block the passage of Scaliger or allied troops through Bolognese territory on their way between the Scaliger possessions in Tuscany and the Veneto.
War
1336: Allied offensive across the Piave
On 22 June 1336, Venice and Florence concluded an alliance against the Scaligers, with Florence undertaking to provide for two thirds of the costs of the war. Venice began preparing for war by instituting a board of 25 patricians authorized to conduct the conflict and supervise the recruitment of an army. A militia force of Venetian citizens of military age (between 20 and 60 years old) was called up from each of Venice's six districts. Contingents of approximately 1,250 men served in turn for terms of fifteen days in local defence duties in Venice and its Lagoon, particularly opposite the Scaliger saltworks and the new Castello di Saline.
Unlike Venice, Florence had extensive experience with contracting and maintaining large mercenary armies. German and Italian mercenaries were recruited, along with cavalry contingents from Florence, Bologna and Ferrara, as well as numerous Venetian citizens who were conscripted or volunteered to serve, swept up by a wave of popular enthusiasm for the war. By September, the allied field army at Motta numbered 4,200 knights and 3,000 infantry; in addition to their pay, the mercenaries were promised any booty they could take, while land and prisoners were to be handed over to the Venetian officials. Command of the joint forces was given to the condottiero Pietro de' Rossi, who had personal reasons to fight against the Scaligers: he and his family had been deprived of their lordship over Parma by Mastino II and his Parmesan allies, the Da Correggio family. The latter became the Scaliger governors, and soon confiscated most of the Rossi estates. Pietro's brothers Rolando and Marsilio secretly left for Venice in early spring, where Marsilio assumed temporary command of the Motta camp while Pietro first took up service with Florence in May before making for Venice, where he arrived in August or September to take up the high command. A council of four, two Venetians and two Florentines, was instituted to advise and assist the alliance's captain-general.
Hostilities began in July, when the allied army captured Oderzo, only to promptly lose it to a Scaliger counterattack. On 23 October Pietro de' Rossi led his forces across the Piave River into the environs of Treviso, divided into three parts: a vanguard of 1,000 infantry and 1,000 cavalry under Marsilio, a rearguard of 400 cavalry and 300 infantry under Golfard Steinberg, and the main army under Pietro himself. Mastino and Alberto opted to avoid a—potentially disastrous—direct confrontation with the allied army, instead engaging in a scorched earth policy. This allowed Pietro de' Rossi to cross the Brenta River unopposed, and advance to Piove di Sacco and thence to Bovolenta, just 12 kilometres (7.5 mi) south of Padua, where the allies set up camp. From there, a detachment was sent to attack the Castello di Saline, which was captured on 22 November and razed to the ground. The allies spent the remainder of the winter pillaging the environs of Padua. The only clash occurred on 26 December, when a force of Veronese knights was defeated at Este; over 150 knights and 26 officers were taken prisoner.
1337: The defection of Padua
In the early months of 1337, Pietro de' Rossi continued his raids into Scaliger territory, partly in order to provision his own army. The town of Curtarolo and the fortress of Treville were captured from the Scaliger lieutenant Guglielmo Camposampiero and garrisoned. At the same time, the rulers of Lombardy, Azzo Visconti of Milan, Ludovico I Gonzaga of Mantua, and Obizzo III d'Este of Ferrara and his brother Niccolò II d'Este of Modena, sent an embassy to Venice to mediate for an end to the conflict. Mastino had held talks with Azzo Visconti at Cremona for this purpose, but once at Venice, the ambassadors agreed to join the Venetian–Florentine league against the Scaligers instead. The conclusion of this alliance on 10 March 1337 was followed on 28 July by the adherence to the anti-Scaliger coalition of John of Bohemia's son (and future Holy Roman Emperor) Charles of Luxembourg, and his brother, John, Count of Tyrol. The Scaligers' diplomatic isolation was complete, their enemies now clearly aiming at the destruction of the Scaliger state. These developments also gave the signal for a revolt of several towns in the Treviso area—Camposampiero, Conegliano, Asolo, San Zenone, Cittadella—which were captured by the allies, followed by a siege of Treviso itself.
At the same time, a Lombard army under Luchino Visconti took to the field in the west, threatening Verona itself. Mastino was forced to withdraw most of his forces to the defence of his capital. In June, Mastino confronted the joined allied army, under Luchino Visconti and Marsilio de' Rossi, south of Verona. In view of the Scaliger numerical superiority, Visconti withdrew and abandoned Marsilio de' Rossi with a much smaller force. Mastino failed to press his advantage, allowing his opponents to withdraw under cover of night. Mastino was apparently also able to bribe the enemy commanders, having exacted forcible loans from the citizens of Verona and Vicenza. Mastino then led his forces east to raise the siege of Treviso. Instead of a direct action, however, he hoped to achieve this by threatening the besiegers' supplies, which came from Venice via Pontelongo. The Scaliger lord captured several ships laden with supplies, but again declined a pitched battle with his opponents when they arrived on the scene, and withdrew towards Verona.