Isabella d'Este, Marchesa di Mantua

Links:

The Peerage: http://thepeerage.com/p33160.htm#i331598

Geneall: http://www.geneall.net/I/per_page.php?id=2336

Wikipedia:

English: https://en.wikipedia.org/wiki/Isabella_d%27Este

Isabella d'Este (19 May 1474 – 13 February 1539) was Marchesa of Mantua and one of the leading women of the Italian Renaissance as a major cultural and political figure. She was a patron of the arts as well as a leader of fashion, whose innovative style of dressing was copied by women throughout Italy and at the French court. The poet Ariosto labeled her as the "liberal and magnanimous Isabella", while author Matteo Bandello described her as having been "supreme among women". Diplomat Niccolò da Correggio went even further by hailing her as "The First Lady of the world".

She served as the regent of Mantua during the absence of her husband, Francesco II Gonzaga, Marquess of Mantua and the minority of her son, Federico, Duke of Mantua. In 1500 she met King Louis XII of France in Milan on a diplomatic mission to persuade him not to send his troops against Mantua.

She was a prolific letter-writer, and maintained a lifelong correspondence with her sister-in-law Elisabetta Gonzaga. Lucrezia Borgia was another sister-in-law; she later became the mistress of Isabella's husband.