Diving into the aristocratic period of Venice Republic

Edit by C.B.: To view the demo, access this blogpost with its direct link.


Blog post 3

Continuing our research of the political structure of Venice Republic, during the previous weeks we have been expanding the research of the second (communal) period trying to introduce more information in the existing graphs. Afterwards, we have focused mainly on the third (aristocratic) period of the Republic, discovering and visualizing connections between numerous institutions, in the same way as we did for the second period.

Concerning the work done in the second period, we made same modifications, which can be seen in the Figure 1.

Figure 1: Political structure of the common period
Figure 1: Political structure during the communal period

In comparison to the graph from the second blog post, we have added two features:

  1. The size of the node now 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.
  2. In the old graph, the colours of the connections didn’t have particular meaning. Here, each line is taking a colour of a node (institution) which influences the other node. In this way we may easily see the influence of particular institution. For example, we can see that the Maggior Consiglio is a dominant institution just by looking at the domination of the red links in the graph.

We applied the same approach to the institutions of the aristocratic period. The connections between them can be seen in the Figure 2.

Figure 2: Political structure of the aristocratic period
Figure 2: Political structure during the aristocratic period

As we may notice, the Maggior Consiglio grew bigger and even more powerful. On the other hand, the Concio was extinguished, since its main elective role lost its purpose. Ordinary people could not enter the institutions anymore and only aristocrats could have been 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, which main function was to decide who can be the member of other institutions, was not needed any more and it was abolished in 1423 AD.

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 Commune Veneciarrum was replaced by the Serrenissima Signoria.

Election of the Doge

We also wanted to depict the protocol used for electing the Doge of Venice [1]. 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. The protocol used for electing the Doge is depicted in the Figure 3.

Figure 3: Protocol for electing the Doge
Figure 3: Protocol for electing the Doge

As we may notice from the Figure 3, 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 the Figure 3. 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 just inside certain number of these balls, which is written as the name of that group in the Figure 3, was a piece of parchment on which was written “Lector”. The men from the group which 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 3, 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.

Distribution of the power between institutions

After analysing main institutions in all three periods of the Republic of Venice, we wanted to show how the function of these institutions was traversed from one institution to another. This is showed using Sankey diagram which we implemented using d3 script and the knowledge of JavaScript. We started with the institutions from the ducal period. At that time, Curia Ducis had the judicial power, Ducal Gastaldi had the administrative power and Consilium Sapientes had legislative and executive power. These two were later separated with foundation of Commune Veneciarum in 1143 AD, which was the government of the Republic.

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 through years until they finally become only the symbol of the Venice.

We are slowly reaching the end of our project. Our plans before the end are to graphically present the structure of the Quarantia and also the administrative structure of the Republic of Venice where the particular importance had the Magistrati.

[d3-source canvas=”chart”]

var margin = {top: 50, right: 1, bottom: 6, left: 150},
width = 750 – 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 4: Transferring power from one institution to another


[1] The Chronicles of Venice: How the Doges Were Chosen, Paul Halsall, November 1998