The Colleoni are an ancient noble family, originally from Bergamo. When the dukes of Milan of the Visconti family conquered Bergamo, they had supporters of the Guelph party, including the Colleoni, who went into exile.
Paolo Colleoni conquered the castle of Trezzo in 1404 and kept it until he was assassinated by his relatives, perhaps on behalf of the Visconti. His son was the most famous member of the family, the condottiere Bartolomeo Colleoni, captain general of the Republic of Venice. He and his daughter Medea († 1470) are buried in the Colleoni Chapel in Bergamo, a significant Renaissance monument. Andrea Verrocchio built for him an equestrian statue in Venice, which is counted among the most important sculptures of the Italian Renaissance.
Another member of the family was Margherita Colleoni (1455-1483), first wife of the military commander Gian Giacomo Trivulzio, buried in the Trivulzio Chapel of San Nazaro Maggiore in Milan.
Bartolomeo's nephew, Alessandro Martinengo Colleoni, commissioned Lorenzo Lotto for the Pala Martinengo for the Dominican church of the saints Bartolomeo and Stefano in Bergamo.
After Northern Italy in the 16th century passed under Austrian rule, it was verified that the Colleoni passed into the service of the Habsburgs.