Editing Isabella d'Este (section)

=== Regency ===
[[File:Leonardo da Vinci, Portrait of Isabella d'Este.jpg|left|thumb|[[Portrait of Isabella d'Este (Leonardo)|Portrait of Isabella d'Este]] by [[Leonardo da Vinci]] (1499–1500)]]
Isabella played an important role in Mantua during troubled times for the city. When her husband was captured in 1509 and held hostage in Venice, she took control of Mantua's military forces and held off the invaders until his release in 1512. In the same year, 1512, she was the hostess at the Congress of Mantua, which was held to settle questions concerning Florence and Milan. {{sfn|Marek|1976|p=250}} As a ruler, she appeared to have been much more assertive and competent than her husband. When apprised of this fact upon his return, Francesco was furious and humiliated at being surpassed by his wife's superior political ability. This caused their marriage to break down irrevocably. As a result, Isabella began to travel freely and live independently from her husband until his death on 19 March 1519.<ref>{{Cite web |title=Brooklyn Museum: Isabella d'Este |url=https://www.brooklynmuseum.org/eascfa/dinner_party/place_settings/isabella_d_este |access-date=5 December 2022 |website=www.brooklynmuseum.org}}</ref>

After the death of her husband, Isabella ruled Mantua as regent for her son [[Frederick II, Duke of Mantua|Federico]]. She began to play an increasingly important role in Italian politics, steadily advancing Mantua's position. She was instrumental in promoting Mantua to a Duchy, which was obtained by wise diplomatic use of her son's marriage contracts. She also succeeded in obtaining a [[Cardinal (Catholicism)|cardinal]]ate for her son [[Ercole Gonzaga|Ercole]]. She further displayed shrewd political acumen in her negotiations with [[Cesare Borgia]], who had dispossessed [[Guidobaldo da Montefeltro]], [[duke of Urbino]], the husband of her sister-in-law and good friend [[Elisabetta Gonzaga]] in 1502.{{citation needed|date=February 2024}}