Government papers did not stop for a birth. Maria Theresa kept working on them through her labour, while the courtiers who might once have crowded round her bed waited in another room. When the baby came, her husband went out to give them the news. The empress went back to signing.

On 2 November 1755, at the Hofburg in Vienna, Maria Theresa gave birth to a daughter, Maria Antonia. The mother was thirty-eight, and this was her fifteenth child. The baby would one day be Queen of France, as Marie Antoinette. For now she was an Austrian archduchess, and one more name in a very large nursery.

She belonged to an enormous family. Her father, Francis Stephen, was Holy Roman Emperor, while her mother ruled the Habsburg lands in her own right. Maria Antonia was their youngest daughter, although she would have one younger brother. Maximilian Franz arrived the following year, completing a family of sixteen children. Such numbers can make the nursery sound impossibly crowded. Several children had already died, and the eldest surviving siblings were approaching adulthood when Maria Antonia was born. She entered a household holding very different stages of family life at once.

Her arrival had its own ceremony. Maria Theresa had ended the old practice of allowing courtiers into the room during a royal delivery. They waited nearby in the Mirror Room, and Francis Stephen came out to announce the birth. His wife had worked on state papers during her labour, and once the child was born she returned to signing them in bed. The closed door kept the court out. The papers came in anyway.

Even her birthday was fitted into an older order. She had been born on All Souls' Day, when Catholics pray for the dead, and during her childhood her birthday was generally kept a day early, on All Saints' Day. The date was hers. The calendar belonged to the Church.

Maria Antonia grew up in the imperial world of the Hofburg and Schönbrunn, with governesses and tutors responsible for much of her daily care. Her mother directed the children's upbringing and expected their conduct to reflect their position. Being one of the youngest offered no exemption from belonging to the dynasty. Each child carried the family name into public life, and Maria Theresa took that responsibility as seriously as anything on her desk.

There was affection in this family, but there was also a formidable standard to meet. The empress could be severe, and her children received unequal shares of her favour. She liked to appear surrounded by them before important visitors. A large, flourishing family made a statement about the woman at its centre. For a little girl growing up inside that arrangement, family life and public appearances happened in the same rooms.

Music and dancing were substantial parts of Maria Antonia's education. Her music teacher was Christoph Willibald Gluck, one of the leading composers of the age, which says something about how seriously the household took the subject. At court, performing well in front of others was a genuine skill, and the imperial children had regular chances to practise it. Birthdays, name days and weddings all brought occasions to sing, dance and act before the family and the court.

The lessons were not only for the schoolroom.

In January 1765, when Maria Antonia was nine, she appeared with her brothers Ferdinand and Maximilian in a pastoral ballet, Le Triomphe de l'Amour. The occasion was the second marriage of their eldest brother Joseph, to Josepha of Bavaria. Pietro Metastasio supplied the text and Florian Leopold Gassmann the music. The three youngest children danced for the eldest son.

Their older sisters performed too, singing and dancing as Apollo and the Muses in a separate work with music by Gluck. This was a family in which the children could furnish the entertainment for a royal wedding, and the youngest daughter had her part in it.

A painting of the ballet shows the three youngest children in their costumes, Maria Antonia beside her brothers. It still hangs in the Hofburg, the palace where she was born. Nine years earlier the court had waited behind a closed door for news of her, and her father had carried it out to them. Now they watched her dance.