Nancy Reagan was her husband's greatest supporter.
Like Ronald, she was a former Hollywood performer who made it all the way to the White House.
The Reagans' 52-year marriage was once described as the greatest love affair in the history of the American presidency.
"My life really began when I met my husband," she once wrote.
She was born Anne Frances Robbins in New York on 6 July 1921 but was known as Nancy from an early age.
Her father, a car salesman, separated from her mother before she was born.
When she was six, her mother Edith - a stage actress - married Loyal Davis, a wealthy neurosurgeon. Dr Davis adopted Nancy, and she grew up in Chicago.
Intent on becoming an actress, she joined a touring theatre company in 1946. Her stepfather's money cushioned her against the rigours that confront many young would-be performers.
She eventually appeared on Broadway, and finally went to Hollywood, where - as Nancy Davis - she made 11 films between 1946 and 1959. Stardom, however, eluded her.
In 1951 she met Ronald Reagan, who had just divorced his first wife, Jane Wyman. By then he was president of the Screen Actors Guild, and the couple worked together on the film Hellcats of the Navy.
They married a year later and went on to have son and a daughter, Ron and Patti. Reagan also had two children from his first marriage, Maureen, who died in 2001, and Michael.
Nancy Reagan retired from films soon after her marriage and for the rest of her life devoted herself to her family.
When her husband became governor of California - and later president - Nancy, an amalgam of protector and mother confessor, was always just behind his shoulder.
As First Lady, she sought to emulate the style of one of her predecessors, Jackie Kennedy.
To this end, she extensively redecorated the White House, accepted designer dresses worth $1m (£600,000) and a 4,732-piece set of china worth $209,000.
But this spending spree provoked a huge outcry from people outraged by what they saw as profligacy and waste while millions of Americans were losing their jobs.
Public opinion was also swayed by accusations that Mrs Reagan had a frosty personality, often consulted astrologers, and ordered the dismissal of White House chief of staff Donald Regan in 1987.
The former First Lady always rejected the harsh image she acquired during the White House years, and President Reagan himself had to deny that his wife was "some kind of dragon lady".
"I often cried during those eight years," she wrote in her 1989 memoirs My Turn. "There were times when I just didn't know what to do, or how I would survive."
During her time in the White House, Reagan became well-known as an anti-drugs campaigner. Though undoubtedly pithy, her slogan "Just say no" went unheeded by many young Americans who just said "yes" instead.
But there was much public sympathy when in November 1994, Reagan announced that he was in the early stages of Alzheimer's disease.
She nursed him as his mental faculties declined and led the nation's mourning when the former president died, aged 93, in June 2004.
She continued to campaign after his death, notably for US government funding of stem cell research; it brought her into conflict with her husband's fellow Republican, President George W Bush, who was opposed to the plan.
Reflecting on her husband's final years, Mrs Reagan was wistful.
"The golden years are when you can sit back, hopefully, and exchange memories, and that's the worst part about this disease," she said in a 2000 interview on CBS television. "There's nobody to exchange memories with... and we had a lot of memories."
She came out in support of Republican John McCain in his 2008 bid for the presidency, making a public appearance with the candidate in front of her home in the affluent Bel Air district of Los Angeles.
Nancy Reagan's political views encompassed opposition to the legalisation of marijuana and abortions, support for the death penalty and horror at the thought of pre-marital sex, even though she was three months pregnant when she married.
Some saw Nancy Reagan as a political innocent, others as a shrewd behind-the-scenes manipulator, who became more and more the power behind White House appointments.
Whatever the case, she was a central figure in her husband's political life and an unswerving supporter of the man known as the "great communicator".
