The comune came into being on the first of January 2019 from the merger of Tresigallo, which is its seat, and Formignana; the new coat of arms arrived only with a decree of 2024, later transcribed in the state's heraldic book — nearly six years to get a shield. The name of the seat, instead, probably says where it stands: from transcalem, that is beyond the embankment, because for centuries this territory stayed shut behind the dyke that ran west of the village down to the Po, with the valli and the marshes all around. In the Statutes of Ferrara of 1287 Tresigallo appears as a borgo of a few houses in an area surrounded by vast marshes; its pieve is documented from the eleventh century, and its dedication to Sant'Apollinare reveals an origin linked to the Exarchate of Ravenna. To go to Ferrara, until about 1906, you took on the Volano embankment a one-horse, six-seat diligence, punctual every Monday and Friday, which took three and a half hours; for some years there was also the alternative of walking two kilometres to the Valpagliaro lock and boarding the steamboat Graziella, which took just as long.
The most remarkable story, though, is that of one man, told by the source in two instalments. In the second half of the nineteenth century, with the great Ferrara land reclamation, day labour grew strongly here, and it found a great organiser in a very young native of Tresigallo, Edmondo Rossoni. Years later Rossoni was a minister, and from 1930, on his impulse, the town was completely rebuilt with rationalist architecture, as was then done with the new-foundation towns: the post-sanatorium colony, the Domus Tua hotel, the house of the fascio, the public baths, the Hotel Italia, piazza Repubblica. For this Tresigallo is the only new-foundation town recognised as a city of art, and for the geometries and the colours of those buildings they call it the metaphysical city. Older than all that stands palazzo Pio, raised with its tower in the sixteenth century by the Faruffini and renamed in the following century after cardinal Carlo Pio. And a detail worth keeping: in the thirteenth century the archpriest of the pieve was Giovanni da Gaibana, who then became the celebrated calligrapher of the cathedral of Padua.