House of Gonzaga From The Art and Popular Culture Encyclopedia
In 1433, Gianfrancesco I assumed the title of Marquis of Mantua,
and in 1530 Federico II (1500–1540) received the title of Duke
of Mantua. In 1531, the family acquired the Duchy of Monferrato
through marriage. Through maternal ancestors, the Gonzagas
inherited also the Byzantine ancestry of the Paleologus, that
earlier ruling family of Montferrat. A cadet branch of the
Mantua Gonzagas became Dukes of Nevers and Rethel in France when
Luigi (Louis) di Gonzaga, a younger son of Duke Federico II and
Margerita Paleologa, married the heiress. The Gonzaga-Nevers
later came to rule Mantua again, when Louis' son Charles (Carlo)
inherited Mantua and Montferrat, triggering the War of the
Mantuan Succession. Another cadet branch were first sovereign
Counts, later Dukes of Guastalla. They descended from Ferrante,
a younger son of Duke Francesco II of Mantua (1484–1519).
Ferrante's grandson, Ferrante II, also played a role in the War
of the Mantuan Succession.