Infanta Margaret Theresa of Spain (July 12, 1651 – March 12, 1673). By marriage to Holy Roman Emperor Leopold I, Infanta Margaret Theresa was Holy Roman Empress, Archduchess of Austria and Queen of Hungary, Bohemia and Croatia. Infanta Margaret Theresa was also an Archduchess of Austria by right of belonging to the House of Habsburg.
Infanta Margaret Theresa of Spain was the first child of King Felipe IV of Spain born from his second marriage with his niece Archduchess Mariana of Austria, daughter of Holy Roman Ferdinand I (1608-1657) and Infanta Maria Anna of Spain (Felipe IV’s sister).
Because of this avunculate marriage, Infanta Margaret’s mother was nearly thirty years younger than her father.

Infanta Margaret Theresa of Spain, Holy Roman Empress
Margaret’s paternal grandparents were King Felipe III of Spain and his wife Archduchess Margaret of Austria. Her maternal grandparents were Ferdinand III, Holy Roman Emperor and his wife Infanta Maria Anna of Spain, the daughter of her paternal grandparents.
The marriage of her parents was purely made for political reasons, mainly the search for a new male heir for the Spanish throne after the early death of Balthasar Carlos, Prince of Asturias in 1646. Besides him, the other only surviving child of Felipe IV’s first marriage was the Infanta Maria Theresa, who later became the wife of King Louis XIV of France and Navarre.
After Margaret, between 1655 and 1661, four more children (a daughter and three sons) were born from the marriage between Felipe IV and Mariana of Austria, but only one survived infancy, the future King Carlos II of Spain.
Margaret did not develop the serious health issues and disabilities (because of the close consanguinity of her parents) that her younger brother had shown since his birth. During her childhood she was once seriously ill, but survived.
According to contemporaries, Margaret had an attractive appearance and lively character. Her parents and close friends called her the “little angel”. She grew up in the Queen’s chambers in the Royal Alcazar of Madrid surrounded by many maids and servants. The Infanta loved candies, which she constantly hid from the physicians who cared for the health of her teeth.
Both Margaret’s father and maternal grandfather Emperor Ferdinand III loved her deeply. In his private letters King Felipe IV called her “my joy”. At the same time, Margaret was brought up in accordance with the strict etiquette of the Madrid court, and received a good education.

In the second half of the 1650s at the imperial court in Vienna the necessity developed for another dynastic marriage between the Spanish and Austrian branches of the House of Habsburg. The union was needed to strengthen the position of both countries, especially against the Kingdom of France.
At first the proposals were for Maria Theresa, the eldest daughter of Felipe IV, to marry the heir of the Holy Roman Empire, Archduke Leopold. But in 1660 and under the terms of the Treaty of the Pyrenees, the Infanta was married to the French King Louis XIV; as a part of her marriage contract, she was asked to renounce her claims to the Spanish throne in return for a monetary settlement as part of her dowry, which was never paid.
Then began discussion about a marriage between Margaret and the Holy Roman Emperor Leopold I (who was her maternal uncle and paternal cousin).
Leopold I (June 9, 1640 – May 5, 1705) was Holy Roman Emperor, King of Hungary, Croatia, and Bohemia. The second son of Ferdinand III, Holy Roman Emperor, by his first wife, Infanta Maria Anna of Spain, daughter of King Felipe III of Spain and Archduchess Margaret of Austria (Felipe III’s first cousin once removed).

Leopold became heir apparent in 1654 by the death of his elder brother Ferdinand IV, King of the Romans, Bohemia, Hungary and Croatia. Elected in 1658, Leopold ruled the Holy Roman Empire until his death in 1705, becoming the longest-ruling Habsburg emperor (46 years and 9 months). He was both a composer and considerable patron of music.
However, the Madrid court hesitated to agree to this proposal, because the infanta could inherit the Spanish crown if her little brother died.
The count of Fuensaldaña, Spanish ambassador in France, suggested the infanta as a possible bride for King Charles II of England. However, King Felipe IV rejected this idea, replying that the King of England should look for a wife in France.
In October 1662, the new Imperial ambassador in the Spanish Kingdom, Count Francis Eusebius of Pötting, began one of his main diplomatic assignments, which was the celebration of the marriage between the Infanta and the Emperor.
On April 6, 1663, the betrothal between Margaret and Leopold I was finally announced. The marriage contract was signed on December 18. Before the official wedding ceremony (which, according to custom, had to take place in Vienna) another portrait of the Infanta was sent, in order for the Emperor to know his bride.

Infanta Margaret Theresa of Spain, Holy Roman Empress
King Felipe IV died on September 17, 1665. In his will, he did not mention Margaret’s betrothal; in fact, the context in which the document was prepared suggests that the late monarch still hesitated to marry his daughter to his Austrian relative because he sought to ensure her rights as sole ruler of the Spanish crown in case of the extinction of his male line.
Mariana of Austria, now Dowager Queen of Spain and Regent of the Kingdom on behalf of her minor son Carlos II, delayed the wedding of her daughter. The marriage was agreed upon only after intense Imperial diplomacy efforts.
On April 25, 1666, the marriage by proxy was finally celebrated in Madrid, in a ceremony attended not only by the Dowager Queen, King Carlos II and the Imperial ambassador but also by the local nobility; the groom was represented by Antonio de la Cerda, 7th Duke of Medinaceli.

On April 28, 1666 Margaret traveled from Madrid to Vienna, accompanied by her personal retinue. The Infanta arrived at Denia, where she rested for some days before embarking on the Spanish Royal fleet on July 16, in turn escorted by ships of the Order of Malta and the Grand Duchy of Tuscany.
Then (after a short stop in Barcelona because Margaret had some health issues) the cortege sailed to the port of Finale Ligure, arriving on August 20. There, Margaret was received by Luis Guzman Ponce de Leon, Governor of Milan.
The cortege left Finale on September 1, and arrived in Milan ten days later, although the official entry was not celebrated until 15 September. After spending almost all September in Milan, the Infanta continued the journey through Venice, arriving in early October in Trento.
At every stop Margaret received celebrations in her honor. On October 8, the Spanish retinue arrived at the city of Roveredo, where the head of Margaret’s cortege, Francisco Fernández de la Cueva, 8th Duke of Alburquerque officially handed the Infanta to Ferdinand Joseph, Prince of Dietrichstein and Count Ernst Adalbert von Harrach, Prince-Bishop of Trento, representants of Leopold I.
On October 20, the new Austrian cortege left Roveredo, crossing the Tyrol, through Carinthia and Styria, and arrived on November 25, at the district of Schottwien, twelve miles from Vienna where the Emperor came to receive his bride.
Holy Roman Empress
The Infanta formally entered Vienna On December 5, 1666. The official marriage ceremony was celebrated seven days later. The Viennese celebrations of the imperial marriage were among the most splendid of all the Baroque era, and lasted almost two years.
Despite the age difference, (the Emperor was 11 years her senior) and Leopold I’s unattractive appearance and Margaret’s health problems, according to contemporaries they had a happy marriage. The Empress always called her husband “Uncle” and he called her “Gretl”. The couple had many common interests, especially in art and music.

During her six years of marriage, Margaret gave birth to four children, of whom only one survived infancy:
Maria Antonia (1669 –1692), Archduchess of Austria, who inherited her mother’s claims to the Spanish throne, married Maximilian II Emanuel, Elector of Bavaria and was the mother of Joseph Ferdinand of Bavaria, claimant to the Spanish throne.
The Empress reportedly inspired her husband to expel the Jews from Vienna, because she believed that they were to blame for her children’s deaths. During the Corpus Christi celebration of 1670, the Emperor ordered the destruction of the Vienna synagogue and a church was built on the site on his orders.
Even after her marriage, Margaret kept her Spanish customs and ways. Surrounded almost exclusively by her native retinue (which included secretaries, confessors, and doctors), she loved Spanish music and ballets and therefore hardly learned the German language.
Death
Weakened due to six pregnancies in six years (which included four living childbirths and two miscarriages) and four months into her seventh pregnancy, Margaret died on March 12, 1673, at the age of 21. She was buried in the Imperial Crypt, in Vienna.
Only four months later, the widower Emperor – despite his grief for the death of his “only Margareta” (as he remembered her) – entered into a second marriage with Archduchess Claudia Felicitas of Austria, the first child and eldest daughter of Ferdinand Charles, Archduke of Further Austria and Count of Tyrol, by his wife and first-cousin Anna de’ Medici.

Archduchess Claudia Felicitas of Austria, Holy Roman Empress
On her father’s side, her grandparents were Leopold V, Archduke of Further Austria and his wife Claudia de’ Medici (after which she received her first name); on her mother’s side, her grandparents were Cosimo II de’ Medici, Grand Duke of Tuscany and his wife Archduchess Maria Magdalena of Austria.
After Margaret’s death, her rights over the Spanish throne were inherited by her only surviving daughter Infanta Maria Antonia, who in turn passed them to her only surviving son Prince Joseph Ferdinand of Bavaria when she died in 1692.
After Joseph Ferdinand’s early death in 1699, the rights of inheritance were disputed by both Emperor Leopold I and King Louis XIV of France, son-in-law of King Felipe IV and a grandson of King Felipe III of Spain. The outcome of the War of the Spanish Succession was the creation of the Spanish branch of the House of Bourbon in the person of King Felipe V, Margaret’s great-nephew and a grandson of King Louis XIV of France.