The earliest records of the comune's origin are found in a deed dated 10 December 1022, in which Marquis Bonifacio of Tuscany is said to be indebted to the bishop of
Cremona for some land in Palvareto, the oldest nucleus of San Giovanni, which was located around the old parish church. The term "Palvareto" seems to have an etymology connected with "palus," meaning "swamp," and "vetus," meaning "old". There was a castle here, which in 1264 the Ermenzoni family sold to Buoso da Dovara. The manor was reinforced in 1341–45 by
Bernabò Visconti and then destroyed in 1406 by Cabrino Fondulo. The latter immediately had a larger castle erected by Maffeo Moro, completed in 1407. During that century, the lands were disputed between
Venice and
Milan; although in 1441 an agreement left the castles of
Pontevico and San Giovanni to the Milanese, the Venetians, aided by the Gonzagas, stormed the fortress of San Giovanni, retaining it only until 1458, when the Milanese retook it. In 1486 Duke
Galeazzo Sforza enfeoffed the castle to Pietro Carminati, Count "Bergamino," whose son Ludovico married
Cecilia Gallerani [formerly a favorite of
Ludovico il Moro], a poet in Latin and the vernacular, a friend of
Gian Giorgio Trissino and
Matteo Bandello, who gave rise to a small court of artists. In 1620, the fief was sold, along with
Gussola, to Alfonso de Pimentel; it then passed to the Vidoni and De' Soresina families. In 1884 the railway station was opened, located on the Parma-Brescia line, and four years later the tramway from Ca' de Soresini to Cremona was opened, which was discontinued in 1928. In the early twentieth century, a significant textile industry flourished in the village, and a Commercial Credit branch was already operating. Between 1928 and 1947 San Giovanni in Croce was united with
Solarolo Rainerio to form the municipality of Palvareto. The place-name Palvareto was taken up in the name of the Union of Municipalities Palvareta Nova, established in 2010 for the associated management of services, which includes the municipalities of San Giovanni in Croce,
Solarolo Rainerio,
San Martino del Lago and
Voltido. In May 2014, after becoming its owner in 2005 and following a major restoration project, the municipality returned to public enjoyment the monumental and naturalistic complex of Villa Medici del Vascello, now a destination for significant cultural tourism attracted, in particular, by the figure of
Cecilia Gallerani, the subject of the
Lady with an Ermine portrayed by
Leonardo da Vinci, who became Countess of San Giovanni in Croce in July 1492. It was in honor of
Cecilia Gallerani that the
local municipal theater, which features an interesting
Art Nouveau facade, was named in November 2002. == Demographic evolution ==