Diana was the third daughter of Edward John Viscount Althorp, the only son of the 7th Earl Spencer, and Frances Ruth Burke Roche, the youngest daughter of the 4th Baron Fermoy, who married in 1954.
The Westminster Abbey ceremony was the social event of 1954, with the Queen the chief guest.
But in 1967 her parents separated and in June 1968 Diana’s father won an acrimonious court battle for custody of the children. In April 1969, when Diana was eight, the divorce was made final. Shortly afterwards, Diana’s mother married again, to Peter Shand-Kydd, in whose divorce proceedings from his first wife she had been named.
Her parents’ divorce took place as Diana was moving from nursery school at King’s Lynn to Riddlesworth Hall, a preparatory school in Diss, Norfolk.
She came to love the school, but her apprehensiveness stemmed from the feelings of betrayal she suffered at being forced away from her family — especially as her father tried to pick up the pieces of his life after the divorce.
The break-up affected her as deeply as it could an affectionate eight-year-old whose life revolved around her family.
At the age of nine, Diana told her nanny that she would marry only once — and only for love — and never divorce.
The changed circumstances of Diana’s childhood were soon evident. Her mother and Peter Shand-Kydd bought a house on the remote island of Seil, off the west coast of Scotland.
Diana was born in 1961 at Park House on the Royal Sandringham estate, which had been leased to her maternal grandfather, Lord Fermoy, by George V as a gesture of thanks for loyal service.
Before her mother left Park House, it had been an idyllic place in which to grow up, surrounded by Norfolk countryside and near the family’s private beach hut at Brancaster.
The Queen’s estate was about a mile away, and the young princes Andrew and Edward frequently visited to swim in the pool.
The child Diana had a desire for drama, once locking a nanny in a bathroom and throwing the underclothes of an au pair on to the roof of the house.
Those happier family times were poignantly displayed at the Diana Memorial Concert at Wembley this year after her younger brother, Charles Spencer, the 9th Earl since 1992, released home cinema footage of children playing gaily in the house grounds.
There was also, however, at Sandringham parish church, the grave of their brother John, the firstborn son, who had lived for just a few hours.
In 1975, when Diana was 13, the 7th Earl died and her father Johnny Althorp succeeded to the title, moving to the family’s ancestral Northamptonshire home of Althorp.
Diana’s final resting place is on a secluded island within the grounds of her family seat but it is not a place where she herself had much of a connection. She was already at boarding school and would not return to the Spencers’ Northamptonshire seat for any significant length again.
During the trial of former butler Paul Burrell, letters revealed she fell out with brother Charles when he rejected her request to secure a “bolthole” on the estate as it would cause too much disruption to his family.
After the divorce, Lord Spencer spent many lonely years struggling in his relationship with his children, who were affected by a sense of divided loyalty between him and their mother.
Then, in 1977, he married Raine, the daughter of Dame Barbara Cartland.
Relations between stepmother and her new children — Diana especially — were heavily strained and Althorp became something of a battleground.
Around the same time, Diana followed her two elder sisters, Sarah and Jane, from Riddlesworth Hall to another girls’ school, West Heath, near Sevenoaks, in Kent, where Earl Spencer was a governor.
During her time there, Diana began to excel at games, particularly swimming, but she failed all her O levels. Despite winning seldom-given awards for helpfulness, she had little academic ability and froze in exams.
In 1977 she went to finishing school at the Institute Alpin Videmanette in Rougemont, Switzerland. Miserably homesick, she left before her course ended and returned to England to work as a nanny.
In the autumn of 1978, she completed a cooking course in Wimbledon and the following year her mother bought her a flat in Coleherne Court, South Kensington, which she shared with a group of close friends.
In April 1979, she started working as an assistant at the Young England Kindergarten, in Pimlico.
She continued to work there until her engagement to Prince Charles was announced in February 1981.