The Tiepolo conspiracy or Tiepolo-Querini conspiracy was an attempt to overthrow the government of the Republic of Venice under Doge Pietro Gradenigo. Headed by the disaffected patricians Bajamonte Tiepolo, Marco Querini, and Badoero Badoer but backed by a sizeable number of other patricians, churchmen, and commoners, the conspiracy resulted in a coup attempt on 15 June 1310, in which three columns, each led by one of the chief conspirators, were meant to converge on the Piazza San Marco, seize the Doge's Palace, and overthrow the Venetian government. Warned of the plot at the last minute, the Doge mobilized his followers and loyalist forces. Coupled with the conspirators' poor coordination, the Doge's decisive counter-action led to the coup's failure. Querini, the main driving force of the conspiracy, was killed in the subsequent fighting along with one of his sons. Badoer was captured while trying to cross the Venetian Lagoon from Padua and executed for treason. Tiepolo was pushed back and barricaded in the Rialto. The Great Council let Tiepolo and his main supporters leave in exile.
Various motives have been attributed to the conspiracy, from personal ambitions to a populist reaction to the increasingly exclusive, aristocratic nature of the Venetian state after the Serrata of the Great Council that excluded the lower classes from power. As the grandson and great-grandson of Doges and son of the commoners' candidate in the 1289 election against Pietro Gradenigo, Tiepolo was the heir to his family's perceived championship of the lower classes against Gradenigo, the candidate of the established families of the traditional aristocracy. In later times, Tiepolo was seen as a heroic champion of the people, but modern historians view the conspiracy as factional strife among the patrician elites, exaggerated by the recent and disastrous War of Ferrara and the resulting papal interdict over Venice.
After the coup's suppression, a policy of public damnation of the participants followed. The houses of Tiepolo and Querini were torn down and replaced with monuments warning against treason. Ordinary citizens who helped in resisting the coup were prominently rewarded and celebrated in subsequent legend. The Council of Ten was established to monitor the conspiracy's exiles and any attempt to subvert the Venetian regime. Initially a temporary measure, the Council proved efficient, and was made permanent, becoming one of the most powerful institutions of the Venetian government.
Background
In the 13th century, the government of the Republic of Venice relied on a series of councils. At the base was the general assembly of the people, which met rarely to ratify legislation. Then followed the Great Council, which was responsible for electing all magistrates and the members of the higher councils. As a result, it was the Great Council rather than the Assembly that held power, but even so, the Great Council was too large and unwieldy for effective deliberation and government. Two other, smaller councils, the Council of Forty and the Senate, provided deliberation and took most decisions in policy. The executive was headed by the Ducal Council and the Doge of Venice, along with the three heads of the Forty. Although chosen for life and enjoying great prestige and authority, the office of Doge was not hereditary and its power was carefully restricted to prevent it from becoming a monarchy.
Venetian politics had traditionally been dominated by an aristocratic upper class, the patricians. In the second half of the 13th century, this aristocratic predominance was challenged by the middle class commoners, wealthy merchants and artisans, who had the backing of the lower classes. At the same time, within the aristocracy itself, factions began to emerge around the Tiepolo and Dandolo families and their respective adherents, when Giacomo Tiepolo won election as Doge in 1229 through a tie-break castling of lots against Marino Dandolo. The Tiepolo represented the newly prominent families that had risen in the aftermath of the Fourth Crusade and the expansion of Venice's commercial and colonial overseas empire, as well as middle-class artisans and guilds, while the Dandolo represented the established old aristocracy.
The challenge posed by the commoners, possibly in alliance with a populist Doge, spurred the ruling oligarchs to reforms to limit the Doge's power through the six ducal councillors—who were meant to not only serve as the Doge's advisors, but also as checks to his authority as they were able to veto his decisions—instituting prohibitions on bearing arms in the Piazza San Marco or the vicinity of the Doge's Palace, and restrictions on the activities of guilds and their members, effectively destroying their political power. In order to defuse factional rivalries and prevent the repetition of 1229, the measures also included the creation of an elaborate system for the election of the Doge, although on its very first application in 1268, Giacomo's son Lorenzo Tiepolo was elected; much to the rejoicing of the commoners and the chagrin of the old elites. Once in office, however, Lorenzo Tiepolo adopted a moderate course, reconciling with his rival (and eventual successor as Doge) Giovanni Dandolo and upholding the restriction placed on the guilds by his predecessor. When Dandolo died in 1289, the commoners loudly proclaimed their support for Lorenzo Tiepolo's son Giacomo, but the latter's very popularity, along with the threat of a quasi-dynastic succession of a son and grandson of doges, resulted in the election of Pietro Gradenigo, scion of one of the great aristocratic houses.
Gradenigo's long tenure as Doge was not tranquil nor very successful in foreign policy. A conflict with Venice's traditional rival, Genoa, ended inconclusively after the Venetians suffered a shattering defeat at the Battle of Curzola in 1298, and while a brief conflict with Padua over Venice's salt extraction monopoly was more successful, the Doge's 1306 treaty with Charles, Count of Valois to launch a crusade for the conquest of Constantinople from the Byzantine Empire and the re-establishment of the Latin Empire with Charles as emperor went nowhere. Gradenigo also spearheaded, ignoring the other executive councils of the Venetian government, the disastrous attempt to capture Ferrara in 1308–1309, which led to a papal interdict and resulted in severe financial losses and a humiliating retreat for the Republic. Venice was simultaneously also embroiled in conflict with the Patriarchate of Aquileia (1309) and faced a revolt in the Dalmatian city of Zara (1310).
Domestically, Gradenigo presided over a major reform of the Great Council. Until then, membership to the council was ex officio, while other members were nominated by a board of four men chosen by lot. While dominated by aristocrats, there were also commoners in the council, as well as Venetian citizens born overseas or recent immigrants. In 1297, in the so-called Serrata (lit. 'lockout') of the Great Council, membership was restricted to those families already holding or having held membership in the previous four years. This measure increased the size of the council and broadened the Venetian ruling class. Initially the admission of new members was allowed, but was soon heavily restricted; by 1323, membership was essentially hereditary, and thus the new dividing line between nobles and commoners. In the long term, the Serrata not only served to exclude the commoners from power, but also helped address rivalries among the patrician elites, by enlarging membership to such a degree that the council could not be dominated by a single faction, and conversely guaranteeing the elites a seat at the table, thus helping Venice avoid the zero-sum factional conflicts plaguing other Italian cities of the time. The Serrata was soon challenged by those excluded from the Great Council: a conspiracy was led by the commoner Marino Boccono in 1300 but little detail is known about it other than that it failed and its members were condemned to death. At least one later source however claims that the Boccono's followers were unhappy at the election of Gradenigo as Doge over Giacomo Tiepolo.
Conspiracy
By 1310, the impact of the Ferrarese war and the Serrata had polarized Venetian society into two opposed parties. The divisions came to the fore during a debate of the Great Council on the Ferrarese question in October 1308, when the papal interdict was announced: the debate descended into chaos, as insults and even blows were exchanged. The two factions even adopted the "Guelph" (pro-papal) and "Ghibelline" (anti-papal) labels that had been current in Italian politics for the past two centuries but not otherwise seen in Venice until then; in Venice they reflected less sympathy for the papacy and more an anti-government and pro-government affiliation respectively. While generally restricting the eligibility for Venetian citizenship and high office, Gradenigo's government was generous with its supporters and allies: in the aftermath of the Bocho affair, the government gave membership in the Great Council to fifteen prominent commoner families that had shown loyalty to the regime, while foreign potentates like Marquis Fresco d'Este, Lord of Ferrara in northern Italy and Count Doimo of Veglia in Dalmatia were given the privilege of bearing arms in public. Much of the opposition's ire focused on Doge Gradenigo, who was held personally responsible for the Republic's state of affairs—arguably so for the Ferrarese war, less justifiably so in the case of the Serrata, as he was mostly the figurehead for the conservative aristocrats who had sponsored his election and were the driving force behind the changes to the Great Council.
In 1310, a conspiracy was formed against Gradenigo and his government, spearheaded by three patricians: Bajamonte Tiepolo, son of Gradenigo's rival Giacomo and grandson and great-grandson of the two Tiepolo doges, his father-in-law Marco Querini, and Badoero Badoer. Not much is known about Marco Querini's life, and he appears to have held but a few political offices, although he served as envoy to Padua during the salt war. His family had extensive estates in Ferrara and Polesine, and were landholders rather than merchants, thus at odds with most of the Venetian aristocracy of the time, and liable to take a more pro-papal stance. He had fought without success in the War of Ferrara in summer 1309 and been captured by Alboino I della Scala, lord of Verona; pro-government figures held him responsible for the loss of Castel Tedaldo in Ferrara, and the Republic did not seek his release until January 1310. Marco was joined by his brothers, Pietro, and Giacomo. Pietro, who had formerly served as Bailo of Negroponte, was of an irascible temper and had most recently gotten into trouble by assaulting a member of the Morosini family—among Gradenigo's chief supporters—who as head of the night watch tried to inspect him for carrying concealed weapons. Giacomo on the other hand had a record of public opposition to Gradenigo and his policies stretching back to the Doge's election, but was by inclination a moderate. Badoero Badoer was the brother of Marco Querini's wife, Maria. Both Badoero and his brother, Marino, had married into families from Padua and its region. In 1309, when Count Doimo of Veglia was elected ducal councillor, Marco and Jacopo Querini led the opposition to this against the Michiel and Giustinian families, leading to a stormy debate and even scuffles in the Great Council, as the Querini brothers and Badoero Badoer brought up a law of 1267 that prohibited the Dalmatian nobles from holding seats in the Great Council or the Senate. The measure nevertheless passed, which deepened the political rift further.
As the oldest and most eminent representative of the "Guelph" faction, and further embittered over his being scapegoated over the failures of the Ferrarese war, Marco Querini was the driving force of the anti-government conspiracy. He was however elderly, being born c. 1245, and thus chose his son-in-law as the revolt's figurehead. Tiepolo was young and popular with the common people, who called him the 'Great Cavalier' and idolized him on account of his illustrious ancestry. His official career began inauspiciously, as he was convicted of embezzling a large sum of money during his tenure as governor of Modon and Coron, where he had lived in a lavish fashion more suited to a prince than a Venetian official. Some modern historians support the notion that the conviction was the result of blatant manipulation by the rival Dandolo family, but historian Frederic C. Lane considers Tiepolo as "the kind of man who justified the aristocracy's fear of giving too much prestige to one family". Although Tiepolo was elected to the Council of Forty in 1304, in the subsequent years he appears to have withdrawn from politics to his country villa near Treviso. The conspirators amassed a considerable following: 77 patricians took part from no fewer than 28 families (although the Querini, Tiepolo, Badoer, and Barozzi provided almost half of them), along with 23 clerics and unknown numbers of commoners. The motives of both leaders and followers are unclear, and were likely as diverse as the plot's membership. Querini and Tiepolo had personal grievances, while some of the patricians, including Badoer and the Querini, also had extensive estates in Ferrara and possibly shared opposition to the war. The conspirators from the clergy were likely also driven by opposition to the war that had brought the papal interdict, while the commoners may have been motivated by patronage ties to patricians, opposition to the costly war of which they bore the brunt of losses, or by the image of the Tiepolos as champions of the common folk and Bajamonte as the man to reverse the Serrata once in power.