Political structure


Over the course of the last few months we have been collecting the data needed for visualization of the political structure of the Republic of Venice in the period from 697 to 1797. At the beginning of the project, our team has already generated a number of initial research questions which we believe could reveal telling patterns through data visualization:

  • Was the Doge the only person who held absolute power throughout the history of the Republic of Venice?
  • Was there any tendency towards a hereditary form of the Doge?
  • Were there any institutions which assisted Doge in ruling the Republic of Venice?
  • Was there any corruption in elections of the Doge?

To find the answers to these questions, we have tried to visualize connections between different institutions in the Republic of Venice. By getting deeper insight about the Venetian political system, we have tried to enrich our graphical representation by adding new connections between the existing institutions as well as to add newly discovered ones.

Methods and Results

We have divided our work into three phases which correspond to the following historical periods:

  1. The ducal period
  2. The communal period
  3. The aristocratic period
The ducal period (742 – 1032)

While we were working on the ducal period, we ran into a problem of lack of data. In almost all literature we analyzed there existed no detailed description of political structure during this period. However, during this period it is clear that the Doge held absolute power and that there were four institutions that assisted him in ruling the Republic of Venice. Firstly, the Concio was established at the beginning of the ducal period (~ 742 A.D.) and functioned as the republic’s general assembly with the ability to elect the Doge. The Concio gradually began to erode the power of the sovereign, finding a valuable ally in the Consilium Sapientes, which was actually the personal board of the Doge and which held legislative and executive power. Judicial power was held by the Curia Ducis. Like most Venetian institutions of this period, the Curia was controlled by the Doge. Administration was handled by the Ducal Gastaldi, officials who performed a similar role to the tribunes of Ancient Rome. The possibility of automatically transmitting the power was taken away from the sovereign. Due to this, the reign turned into a system that was controlled by the most powerful patrician families that began to contend for the throne. The political structure during the ducal period can be seen in figure 1.

Figure 1: Political structure during the ducal period
Figure 1: Political structure during the ducal period
The communal period (1032 – 1296)

This period started in 1032 when the Doge was beginning to weaken, surrendering power to the Concio and Consilum Sapientes. Later, as the Consilum Sapientes gained more and more power, new institutions such as the Maggior Consiglio, Quarantia, Minor Consiglio and Consiglio dei Pregadi, replaced the Consilum Sapientes. These new institutions had far more power than the Doge, who by this time functioned as little more than a figurehead, responsible for mostly ceremonial duties. The main functions of Consilum Sapientes were inherited by the Maggior Consiglio which became the highest organ of the Republic of Venice. Another of the most important institutions of this period was the Quarantia, which functioned as the government and supreme court. Administration of the most sensitive and urgent issues of the period was entrusted to the Consiglio dei Pregadi, an assembly of restricted membership. However, main control over the Doge was exerted by the Minor Consiglio which consisted of just six ducal councillors. In 1268 A.D. the new position of Grand Chancellor was established. As supreme head of the bureaucracy palatine he was the most important Venetian except for the Doge himself. Aside from these many institutions, the government of the city of Venice, called Commune Veneciarum, was also established during this period. In order to get better insight into the political structure of this period we used Gephi, which is an interactive visualization and exploration open source platform for numerous networks and complex systems, using dynamic and hierarchical graphs. The political structure during the communal period is depicted in figure 2.

Figure 2: Political structure during the communal period
Figure 2: Political structure during the communal period

In figure 2 the size of the node represents the number of people forming each institution – it depicts the distribution of power (in terms of the number of people holding it) more accurately. Each line between two nodes takes the colour of the node (institution) that influences the other. In this way we may easily see the influence of particular institution.

The Aristocratic Period (1296 – 1797)

In this period, the Maggior Consiglio became more powerful. The Concio was extinguished, since its main elective role lost its purpose. Ordinary people could not enter the institutions anymore and only aristocrats could be elected. In order to distinguish who is an aristocrat, The Golden Book and The Silver Book were introduced with the names of the aristocratic families. So the Concio, whose main function was to decide who could be a member of other institutions, was not needed anymore and it was abolished in 1423 AD. The Commune Veneciarrum was replaced by the Serrenissima Signoria.

The following institutions appeared in this period:

  • The Consiglio dei X
  • Tre Inquisitori de Stato
  • Zonta
  • Collegio (Savi agi Ordini, Savi Grandi, Savi di Terraferma)

The political structure during the aristocratic period is depicted in figure 3.

Figure 3: Political structure during the aristocratic period
Figure 3: Political structure during the aristocratic period
Election of the Doge

In order to figure out if there was any corruption in elections of the Doge, we tried to visualize the protocol used for electing the Doge of Venice. The protocol used for electing the Doge is depicted in figure 4.

Figure 4: Protocol for electing the Doge
Figure 4: Protocol for electing the Doge

As we may notice from figure 4, the election was performed in ten rounds. There were two phases which were repeated. The first phase was a lottery phase and it is denoted with black arrows in figure 4. In this phase a little ball of wax was made for each person who belonged to the group of people from which the black arrow starts, but inside a certain number of these balls, which is written as the name of that group in figure 4, was a piece of parchment on which was written “Lector”. The men from the group who took such a ball were chosen for the next round. The second phase was election phase, where the group of people, from which the grey arrow starts in figure 4, assembled together and chose people for the next group. The grey lines indicate that the men for the next round were elected from Maggior Consiglio, while the ratio on the grey arrows indicates the proportion of agreed people for the election of one candidate. Following the same procedure, the Doge was chosen from the Maggior Consiglio in the 10th round and he was chosen by Quarantia.

The way in which the election was performed reflects the fact that the opportunity was given to minorities while ensuring that more popular candidates were more likely to win. We think that this protocol of electing the Doge might have offered some resistance to corruption and it might have assisted the emergence of compromise candidates by amplifying small advantages. These properties may have contributed to the extraordinary stability and longevity of the Venetian Republic.

In order to sum up everything we have found so far, as well as to show how the function of different institutions was changing through the entire period of the Republic of Venice, we have made a Sankey diagram which we implemented by using d3 script and our knowledge of JavaScript. The power flow between different institutions is depicted in figure 5. In this diagram we decided not to present the Doge and the Concio as their power was gradually decreased and transferred to all the other institutions over the years until they finally become only the symbol of Venice.

[d3-source canvas=”chart”]
var margin = {top: 50, right: 1, bottom: 6, left: 150},
width = 700 – margin.left – margin.right,
height = 500 – margin.top – margin.bottom;

var formatNumber = d3.format(“,.0f”),
format = function(d) { return formatNumber(d); },
color = d3.scale.category20();

var svg = d3.select(“.chart”).append(“svg”)
.attr(“width”, width + margin.left + margin.right)
.attr(“height”, height + margin.top + margin.bottom)
.attr(“transform”, “translate(” + margin.left + “,” + margin.top + “)”);

var sankey = d3.sankey()
.size([width, height]);

var path = sankey.link();

d3.json(“/wp-content/uploads/2014/05/institutions.js”, function(energy) {


var link = svg.append(“g”).selectAll(“.link”)
.attr(“class”, “link”)
.attr(“d”, path)
.style(“stroke-width”, function(d) { return Math.max(1, d.dy); })
.sort(function(a, b) { return b.dy – a.dy; });

.text(function(d) { return d.source.name + ” → ” + d.target.name + “\n” + format(d.value); });

var node = svg.append(“g”).selectAll(“.node”)
.attr(“class”, “node”)
.attr(“transform”, function(d) { return “translate(” + d.x + “,” + d.y + “)”; })
.origin(function(d) { return d; })
.on(“dragstart”, function() { this.parentNode.appendChild(this); })
.on(“drag”, dragmove));

.attr(“height”, function(d) { return d.dy; })
.attr(“width”, sankey.nodeWidth())
.style(“fill”, function(d) { return d.color = color(d.name.replace(/ .*/, “”)); })
.style(“stroke”, function(d) { return d3.rgb(d.color).darker(2); })
.text(function(d) { return d.name + “\n” + format(d.value); });

.attr(“x”, -6)
.attr(“y”, function(d) { return d.dy / 2; })
.attr(“dy”, “.35em”)
.attr(“text-anchor”, “end”)
.attr(“transform”, null)
.text(function(d) { return d.name; })
.filter(function(d) { return d.x < width / 2; })
.attr(“x”, 6 + sankey.nodeWidth())
.attr(“text-anchor”, “start”);

function dragmove(d) {
d3.select(this).attr(“transform”, “translate(” + d.x + “,” + (d.y = Math.max(0, Math.min(height – d.dy, d3.event.y))) + “)”);
link.attr(“d”, path);

Figure 5: Power flow between different institutions


Over the course of the last few months we tried to visualize the complex political structure of the Republic of Venice which was scarcely surprising at the time. On the other hand, our project is also addressing a larger trend within the digital humanities: the increased prevalence of data visualization as a mode of literary interpretation. As the project emphasizes visualization tools as a means to generate new research questions, we believe that our project could provide new insights and approaches to any scholar interested in the use of our data for further historical research.


We would especially like to thank our teacher assistants within the Digital Humanities course at the École Polytechnique Fédérale de Lausanne (EPFL), Mr Giovanni Colavizza and Mr Cyril Antoine Michel Bornet, for their help, encouragement, patience, insightful advice, and constructive feedback during the entire period of our research work. We would also like to thank the professor Frédéric Kaplan for providing us with this project.


[1] http://it.wikipedia.org/wiki/Governo_della_Repubblica_di_Venezia
[2] O’Connell, Monique, Men of Empire: Power and Negotiation in Venice’s Maritime State, 2009.
[3] The Chronicles of Venice: How the Doges Were Chosen, Paul Halsall, November 1998
[4] Edward Muir, Civic Ritual in Renaissance Venice, 1986.
[5] Gamberini, Andrea, and Isabella Lazzarini. The Italian Renaissance State, Cambridge, 2012.
[6] Eric R Dursteler, A Companion to Venetian History 1400-1797, Brill, 2013.
[7] John Julius Norwich, Peter Dimock, A History of Venice, Vintage, 1989.

Mihailo Jokić
Radoslav Pantić
Dionisije Sopić