From 1665 to 1671, she was Regent of the Duchies of Mantua and Montferrat on behalf of her minor son. Accused of marrying her lover without Imperial consent, she was forced to take the veil as a nun and imprisoned at the Ursuline monastery of Mantua until her death.
On 7 August 1649, the marriage contract between Isabella Clara and Charles II Gonzaga, Duke of Mantua and heir of the Duchy of Montferrat, was signed at Innsbruck. Considering the size of the bride's dowry, the contract stipulated that all the revenues of the Gazzuolo district must be given to her.[6][7] The official wedding between them was solemnized three months later, on 7 November[a] in Mantua.[1] Thanks to this alliance with the House of Habsburg, Charles II was able to remove the French from Casale and then agreed with King Louis XIV of France that Spain should not control the Duchy of Montferrat; rather, it would remain with the Gonzaga family.[8]
In Revere on 31 August 1652, Isabella Clara gave birth to her only child, Ferdinand Charles, the future and last Duke of Mantua and Montferrat of the House of Gonzaga; however, this didn't help the couple overcome their differences. Charles II was indifferent to his wife –whom he married purely for political reasons–, and had a long-standing relationship with the Countess Margherita della Rovere, also living at Casale with della Rovere openly. Isabella Clara, with the help of Pope Alexander VII, expelled her husband's mistress to Rome;[9] but this didn't stop the hypersexuality of Charles II, who continued taking lovers, both male and female.[6][7]
Isabella Clara soon tired of her husband's behaviors and, in spite of her mother-in-law's requests that she be prudent, Isabella Clara also took a lover, Count Charles Bulgarini, a secretary of the Duke and a baptized Jew from the Mantua ghetto.[10] They had a secret relationship initially, but the affair became well-known in time. Consequently, Isabella Clara suffered the rejection of and contempt from the ducal court. In June 1661, an assassination attempt was made against the Count Bulgarini, but the shot killed his father. In 1660, after the death of her mother-in-law, Isabella Clara also took the title of Duchess of Montferrat.[11] When Charles II died suddenly on 14 August 1665, there were rumors that his wife ordered that he would be poisoned. In fact, the Duke died either accidentally after drinking an aphrodisiac,[6][7][8] or in the midst of lascivious intercourse.[12]
Regency
During her husband's life, Isabella Clara relied on the advice of her lover and controlled the political situation in the duchy. When she became a Regent on behalf of her minor son, she appointed Count Bulgarini as her First Minister and took a neutral position between the Spanish and French kingdoms and also kept a cautious policy to ensure that Mantua and Montferrat would become independent from the Holy Roman Empire.[6]
In November 1666, she received the ducal investiture from the Holy Roman Emperor on her son's behalf, which confirmed his ownership over the fiefs of Reggiolo and Luzzara that the Dukes of Guastalla had controlled since 1631. During her regency, Isabella Clara increased the Duchy of Mantua's territory, strengthening its defenses. Under the mediation of Luis de Guzmán Ponce de Leon, governor of Duchy of Milan, she also obtained several islands in the Po river without hostility; these were also claimed by the Duchy of Modena and Reggio. In addition, Count Bulgarini used his position to improve the economic situation of the state with several tax, judicial and law enforcement systems [6] and the quality of life of the local population.
Imprisonment and death
In August 1669, the Dowager Duchess ended her regency and transferred all of her powers to her son. However, due to the dissolute behavior of the young duke, she had to continue participating in the affairs of the state. In August 1670, at Goito, Isabella Clara entered into a marriage contract with Ferrante III Gonzaga, Duke of Guastalla, under which their children Ferdinand Charles and Anna Isabella would marry one another. Under this contract, Ferrante III named his daughter and son-in-law joint heirs of the Duchy of Guastalla and the Dosolo, Luzzara and Reggiolo regions. Additionally, the Dowager Duchess obtained the approval of the Emperor that, after the death of Ferrante III (who had no surviving male heirs), the Duchy of Guastalla would be passed to her son, as his wife's inheritance, successfully.[6][13]
After the official wedding ceremony of her son with the Guastalla heiress in July 1671, Isabella Clara retired from court and moved to Goito Castle, where she lived with Count Bulgarini, whom she married secretly shortly thereafter. This may have been why, on 16 December 1671, Leopold I, Holy Roman Emperor imprisoned Isabella Clara in an Ursuline monastery and Count Bulgarini in a Dominican monastery, both having been imprisoned with the consent of the Pope. At the request of the Imperial Commissioner, Count Gottlieb von Windisch-Graetz, both Isabella Clara and Count Bulgarini took monastic vows. The Dowager Duchess became a Poor Clare nun.[6]
Isabella Clara died on 24 February 1685 in the Ursuline monastery in Mantua.[1] Only her son attended her funeral and she was buried in the Church of Sant'Orsola.[14] Her public memorial service took place on 14 May in the Basilica palatina di Santa Barbara.[6]
Ancestors
Ancestors of Archduchess Isabella Clara of Austria
Wurzbach, C. von (2012) [1860]. "Habsburg, Elisabeth auch Isabella Clara von Oesterreich". Biographisches Lexikon des Kaisertums Österreich (in German). Austria: Austrian Literature Online, University of Innsbruck. p. 178.
Ersch, Johann Samuel (2012) [1862]. Allgemeine encyclopädie der wissenschaften und künste in alphabetischer folge von genannten schrifts bearbeitet und herausgegeben (in German). Leipzig: Gleditsch. p. 161, 163, 188.
Generations are numbered by male-line descent from Frederick III, Holy Roman Emperor. Later generations are included although Austrian titles of nobility were abolished and outlawed in 1919.