l Tassini (Curiosità Veneziane, VENEZIA, 1886, p. 75) offers two different interpretations regarding the confiscation of the Querini property.
“Beccarie (Calle, Campo, Ponte, Rio, Calle delle) in Rialto. In this field stands the Querini palace, known as the “Ca’ Mazor”, or “Ca’ Granda” which, after the Tiepolo-Querini conspiracy in 1310, was demolished for two thirds belonging to the conspirators Marco and Pietro Querini, and left intact for another third owned by the innocent Giovanni Querini. Some chronicles, however, say that since the divisional instruments were not found at the time, and since there were some common parts of the house, and therefore indivisible, the government left it standing as it was, but confiscated the two thirds belonging to Marco and Pietro Querini, and bought the third belonging to Giovanni.
It is certain that in 1339 the public beccherie di Rialto were placed here, located first near S. Giovanni Elemosinario where the ‘Drapperia’ was then located. Hence the name ‘Stallone’, which the building retains. Nor should it be forgotten that it returned, albeit briefly, during the siege of Venice in 1849 to serve as a public slaughterhouse, since the one at S. Giobbe was exposed to the hail of balls.
To buy the book “Curiosità Veneziane”: https://www.ibs.it/curiosita-veneziane-ovvero-origini-delle-libro-giuseppe-tassini/e/9788864950624
More info on Rialto fish market: https://www.comune.venezia.it/it/content/rialto-mercato
Official website City of Venice Tourist and Travel Information: https://www.veneziaunica.it/