The earliest historically verifiable facts regarding the Grassi family's decision to build their own residence in the parish of San Samuele date from 1732; Zuanne and Angelo Grassi bought, from Antonio and Bartolomeo Trivellini, a few houses along the Grand Canal, the campo of San Samuele and the calle immediately behind it. The most prestigious building in this lot was the small palazzo occupying the outer area, near the canal, which is clearly visible in many graphic and pictorial representations of the period (it can clearly be seen in the painting by Bernardo Bellotto at the Lyon Museum, for example). But the ambitions of the Grassi family, who moved to their new quarters almost immediately, were not to be satisfied so easily. Their burning desire for visibility was certainly not going to be satisfied by this dignified little palazzo on the Grand Canal. Nor was a display of newly-acquired power or by no means less unequivocal wealth their main aim when they bought this little palazzo - even though this was common practice for almost all the powerful families belonging to the more or less recent Venetian nobility.

While the older and more established families had actually contributed to the constitution of the original allotments and at the same time built the first great series of 13th-century fondaco-houses along the Grand Canal, it was during the resplendent and rampant period of the Venetian Gothic (during the 14th and 15th centuries, and beyond) that Venice was given its immense multicoloured piers and jetties in the ogival style. It was in the period of the Renaissance, however, that the role and form of modern, classical housing was re-proposed and ideologised. Venice was thus also given architectural orders and rules based both on Ancient Roman as well as modern precepts. Sansovino and Sanmicheli were the main interpreters and propagators of this style from the mid-16th century on, and were responsible for effecting that break with what had been the formerly predominant architectural style in Venice and gave rise to a heated dialectics between rules and licence that was to be the mainstay of Venetian architecture for at least the next three centuries (that is, until it definitively came to a close in the Neo-classical period).

The building of monumental marble palazzos, dominating a noble and panoramic site and pitted against the work-a-day, humdrum nature of daily existence (even though it must be said that commercial enterprise was not entirely frowned upon within this noble context, nor did the families necessarily think twice before agreeing to let out parts of their palazzo to other nobles or members of the bourgeoisie for vast amounts of money), was certainly one of the most recognisable and unmistakable signs of a family's newly-acquired status. And it was by no means rare that these ambitions, which sometimes became a burning obsession or an uncontrollable desire for self-promotion and celebration, should require more money than the family actually had. Sometimes these projects therefore went hand in hand with the family's economic ruin.

The Grassi family was no exception, and buying their first allotment was like appearing for the first time on the Venetian stage of real estate, culture, investment and public image.
In 1737, the family's next move was to buy a set of buildings owned by Michiel alongside the Trivellini allotment. This series of buildings was actually somewhat disarrayed and as yet not completely finished, and was dominated by a large, unfinished palazzo which can be seen in a few paintings of the period. This building nonetheless contained a few finished self-contained sections and wooden finishings. Other smaller properties were bought in 1738, along with other acquisitions which continued into the early 1740s. The Grassi allotment grew to such an extent that its lateral extension provided a large opening onto the Grand Canal and the campo. The allotment now covered a large enough area to allow the family to embark on its ambitious project.

It must be pointed out, however, that the pre-existing building or buildings were probably subsumed within the new palazzo. The large wing of the unfinished palazzo bought from the Michiel family probably constituted a structural and dimensional starting point for Palazzo Grassi. Economic reasons and the common practice in Venice of re-utilising already existing buildings, and especially the foundations, make this a reasonable hypothesis, and analyses of the size and orientation of the building help confirm this view.

As the Grassi family archives have been lost, we have no clear indication of the paternity of the Palazzo Grassi project. Art critics, from Moschini (1805) on, have always assumed the author was the architect Giorgio Massari, and there seems to be no valid reason for doubting this authoritative opinion. What's more, a close analysis of the stylemes employed in the building tend to corroborate the view. If anything, what should be underlined is that in the same period Massari was working on the completion and extension of Ca' Rezzonico just across the Grand Canal. This unfinished building had just been bought by the Rezzonico family from the Bon family, and it offers us the opportunity to analyse the similarities and differences in the choices and methods employed by Massari.

A brief summary of the facts culled from available documents would read as follows: when the basic allotment and buildings were bought, the stonecutters were brought in in 1745; the foundations were being worked on in 1748; Angelo Grassi, who had commissioned the "new and beautiful palazzo facing the Grand Canal and San Samuele" (Gradenigo), died in 1748; the building, despite the fact that work was already under way, was augmented and extended in 1766; in 1767 the water-way leading to the building was redone and enlarged; on the death of Paolo Grassi, one of Angelo Grassi's children, in 1772, the building had presumably been completed.

The overall consistency of the finished building would lead us to believe that the enormous Palazzo Grassi structure was brought to completion over a period of about 25 years without any significant interruptions in the construction phase. The additions and reconstruction work (the side giving onto the Grand Canal above all; some repair work, and perhaps extensions undertaken on the northern side of the building which might also have involved the structure of the monumental staircase; perhaps the addition of a floor) do not in the slightest compromise the compact and organic nature of the whole and, once again, Giorgio Massari's reputation is confirmed.