Maria Theresa of Austria (1801–1855)

Maria Theresa of Austria (21 March 1801 – 12 January 1855) was born an Archduchess of Austria and Princess of Tuscany. She was a daughter of Ferdinand III, Grand Duke of Tuscany, and Luisa of Naples and Sicily. She was named after her double great grandmother Empress Maria Theresa. In 1817, she married Charles Albert of Sardinia and subsequently became the Queen of Sardinia upon her husband's accession to the throne in 1831.

Maria Theresia Franziska Josepha Johanna Benedikta (German) was a member of the Tuscan branch of the House of Habsburg-Lorraine and an Archduchess of Austria and Princess of Bohemia, Hungary, and Tuscany by birth. She was born in Vienna during the exile of her parents and their many children, due to Napoleon Bonaparte's invasion of Tuscany. Her father was Ferdinand III, Grand Duke of Tuscany, and her mother was Princess Luisa of Naples and Sicily, who died giving birth to a stillborn son one year after Maria Theresa's birth.

After the Restoration of 1814, Ferdinando III was made Elector of the secularized archbishopric Salzburg and the family moved to Würzburg.

Maria Theresa married in Florence on 30 September 1817 Charles Albert of Sardinia (Paris, 29 October 1798 - Porto, 28 July 1849), and a wedding mass was celebrated on 2 October in Florence Cathedral. In Italian, her name was Maria Teresa Francesca Giuseppa Giovanna Benedetta.

In March 1820, an heir was born followed by two more children, the latter of which died in infancy. From her marriage, she was known as the princess of Carignano. In 1824, Charles Albert was recognised as heir to the throne by Victor Emmanuel I of Sardinia. He and Maria Theresa became king and queen in 1831, when his predecessor Charles Felix of Sardinia died without issue.

After the death of her husband in 1849 in Oporto, the Queen mother Maria Theresa stopped appearing in public and even returned to Italy in 1851, where she died four years later, in Turin. She was buried in the Basilica of Superga in Turin.

A convinced Catholic and conservative, she had a great influence on her eldest son on the new Italian throne.

• Vittorio Emanuele Maria Alberto Eugenio Ferdinando Tommaso (14 March 1820 – 9 January 1878) married Adelaide of Austria and had issue; would become the first King of united Italy;
• Ferdinando Maria Alberto Amedeo Filiberto Vincenzo (15 November 1822 – 10 February 1855) married Princess Elisabeth of Saxony and had issue; Duke of Genoa;
• Maria Cristina (4 July 1826 – 25 July 1827) died in infancy.

Even among the frequently tangled genealogies of European nobility, the ancestry of Maria Theresa of Tuscany was unusual. In fact, her parents had the same four grandparents, so they were double cousins when they spoused: this practice of alliances between cousins that was still common at that time, given that the families (and notably the parents and grandparents of Maria Theresa) had a lot of children, and this avoided to split too much the benefit of heirs though alliances and their descendance, and the multiplication of nobility titles to satisfy the various claims by descendants.

As a consequence, her grandparents consisted of two brother/sister pairs. Her paternal grandfather, Leopold II, Holy Roman Emperor, was the brother of her maternal grandmother, Maria Carolina of Austria. Matching that combination, her paternal grandmother, Maria Luisa of Spain, was the sister of her maternal grandfather, Ferdinand I of the Two Sicilies. As a consequence she only had four great-grandparents rather than the usual eight. (Although not so unusual, it may be worth pointing out that her grandmothers and great-grandmothers, as well as her mother or herself and her sister, or her daughter were all surnamed "Maria".)

• 21 March 1801 – 11 August 1804 Her Royal Highness Archduchess Maria Theresa of Austria, Princess of Tuscany
• 11 August 1804 – 30 September 1817 Her Imperial & Royal Highness Archduchess Maria Theresa of Austria, Princess of Tuscany
• 30 September 1817 – 27 April 1831 Her Imperial & Royal Highness The Princess of Carignano
• 27 April 1831 – 23 March 1849 Her Majesty The Queen of Sardinia
• 23 March 1849 – 12 January 1855 Her Majesty Queen Maria Theresa of Sardinia