In the period of the struggles between the Guelphs and the Ghibellines the local city council was breaking up and in 1273 Pinamonte Bonacolsi took advantage of the situation to transfer power to his family.
Under his short domination lasting about half a century, Mantova was enriched with imposing embattled palaces.
On the two longer sides of Piazza Sordello were built Palazzo Bonacolsi on the left of the Cathedral, and on the right the "Magna Domus" and the Captain's Palace which later on become the Ducal Palace, where the Gonzagas lived for about four centuries.
During the Bonacolsi's domination, the first begging orders come to Mantova, new churches and convents of gotic style arose, among which St. Francis' Church built beetween 1303 and 1304.
In 1328 the last of the Bonacolsi, Rinaldo called the Passerino was killed during a popular riot set on by the Gonzagas. The driving out of the Bonacolsi is painted in a wall known painting by Domenico Morone.