Isabella Gonzaga (1576–1630) was a duchess consort of Mantua and Montferrat as the wife of Vincenzo II Gonzaga, Duke of Mantua.
She was the daughter of Alfonso Gonzaga, Count of Novellara, and Vittoria Capua. Isabella Gonzaga was described as a beauty. She was first married to Ferrante de Gazzuolo, who died in 1605. In 1617, she married her relative Vincenzo Gonzaga, 22 years her junior. His brother Ferdinando, the sovereign duke of Mantua, had appointed him cardinal in 1615, but Vincenzo fell in love with Isabella and dismissed his position of cardinal in 1616 after an appeal to the Pope to make it possible for him to marry her.
His brother opposed their marriage, and eventually Vincenzo himself became unhappy with the match because of the pressure of having children, which Isabella failed to produce. Isabella Gonzaga was accused of witchcraft in an accusation staged by her brother-in-law Ferdinando Gonzaga; her husband eventually supported the accusations. Her husband, however, left Mantua, where he was afraid of being attacked, and transformed the witch trial to the jurisdiction directly under the Pope. In the following witch trial, Isabella was cleared of all charges of sorcery. In 1626, her husband inherited the throne of Mantua from his brother. Though the couple was separated, they were not divorced, which formally made her duchess consort. The couple had no children.
Isabella did have 8 children from her first marriage with Ferrante de Gazzuolo, including
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