With the rise power of the Partecipazio family (811) a fundamentally important event occurred in the history of Venice: to protect the duchy from possible invasions, the Partecipazio family took possession of the Rialto islands.
Here, as a nearly irreversible choice, the building of the Palace began immediately, which became the seat of the Doges for nearly a millennium, despite obvious changes and extensions to the building.
Another event influenced that choice: the discovery of St. Mark’s body and its location in 829 in the adjoining ducal chapel, which gives the area facing the lagoon its predominant feature, the place that symbolizes the power of St. Mark.
The other growth pole of the Rialto islands, beyond the square, developing in front of the public office buildings, was the Rialto market, which was intended to take over completely from the “magnum emporium” of Torcello.
The still restricted area between the small square and the lagoon became the centre of all island settlement as part of an urbanization process that left its mark, above all, in the century to follow.

Right from the start the Piazza was, therefore, at the centre of this unique city that was expanding where water and land meet.
The Piazza is clearly at the crossroads of the pedestrian route that starts at Rialto and meets the Grand Canal at the point where it opens into the lagoon basin: from a nearly natural existence, it gradually took on a more significant and planned aspect.
But over time its function has always remained the same, even if greater importance has been given to its status of power and representation.
Originally water covered a large area of the present Piazzetta and this open space served as an initial landing place for the small port.
According to a later hagiography, a “concio” took place in the Piazza, that is, a public meeting of all the lagoon’s inhabitants from Capodargine to Grado to elect the Doge and decide the most important state issues: in fact, Venetian society soon developed a social rank that divided politics into majores, rich men of property, controlling the salt market and actively involved in trading, mediocres, a middle class comprising salt workers, fishermen, ship builders and artisans and minores who already assumed a more dependent social role. If there was a public meeting, and even if it was formally open to everyone, it became a place where decisions were finalised. With this “agreement“, no longer a plenum, but instead only representatives assembled for previously made decisions, an institutional process began that led, with the increasing power of the majores, to the “Serrata del Maggior Consiglio” (Closure of the Great Council) and to a clear distinction between the noble oligarchy and the rest of the population.

From 900 to 1200 Venice accumulated its wealth from the sea and from its trading and exchange with the East and the West.
We can indirectly trace this process by noting the significant changes that took place in the Piazza at the end of the 12th century.
Until then we can see that the Piazza was a small restricted area crossed by the Batario canal. Here a “brolo” could be found, a small herb and vegetable garden, a sign that the city was not completely urbanized, as we know it today.
At the end of the 1200s, the Ducal Palace building was enlarged, although it was not of the same dimension as it is today, the present Basilica building was completed, the canal was filled in and a brick herringbone pavement was laid, which can still be seen today in some Venetian courtyards.
The Piazza’s dimensions largely resembled those of today: the Campanile was built, a one-time lookout and observation tower over the lagoon, while the Piazzetta was taking shape in front of the Palace towards the quay. Here, on colossal columns brought from the Orient were placed the lion of St. Mark on one side and the figure of Todero (St. Theodore) on the other, the first patron saint of the Venetians before St. Mark.
Around the Piazza new buildings sprang up and in particular, Procuratie Vecchie, as clearly depicted in the painting by Gentile Bellini that illustrates the existing scene in the Piazza in 1496. The term “Procuratie” comes from the appointing of the Procurator of St. Mark. With the increasing number of Venetian courts, these magistrates assumed a role of great prestige and importance and were thus allocated the buildings around the Piazza as residences. The Procurators were divided into “de supra” for the Basilica and related buildings and “de citra” or “de ultra” depending on which of the two banks of the Grand Canal they presided over.