After devoting much of his life to the challenge of preparing his eldest son Charles to rule effectively, Prince Philip showed signs of overcoming doubts over the heir, a family biographer has told The National.
The author, Michel Faure, says the Greek-born consort, who died on Friday two months short of his 100th birthday, set himself a mission to "make a man" of his son and overcome qualms about his fitness to reign.
In his book, Charles, King of England, published last month, Mr Faure charts the roles of sport, military service and shared environmental awareness in easing a difficult relationship.
Faure, a veteran French foreign correspondent and author, detects a gradual shift in father-son dynamics as the "attentive but authoritative" Duke of Edinburgh began to recognise Prince Charles's efforts to show himself worthy of his rank and of his father.
But he feels that the prince only partly won his father’s trust, and continued to fear as well as admire him in a relationship which continued to be ambiguous. "His son feared him while at the same time admiring him," Faure says now. "And this mixture of fear and admiration has continued."
Faure recalls how, as recently as 2017, the duke implied that he did not consider his decades-long project to shape his son as a dependable future king to have been an unqualified success.
He views as a key moment, first revealed by biographer Tom Bower, when the duke was quoted as questioning his son’s suitability for the monarchy.
At a dinner with friends, Prince Philip is said to have described Queen Elizabeth, then 91, as being in robust health and likely to live for at least 10 more years. "Charles would have little opportunity to damage the monarchy if he were king for only a brief period," he reportedly added.
Bower's own account says that the duke also voiced doubts about whether his son "who had barely come to terms with the 20th century, could unify the country in the 21st".
Speaking to The National after the Duke of Edinburgh's death, Faure accepted that if the remarks were accurately reported, they may have reflected the royal consort's "sometimes questionable humour", intended to amuse chums at a convivial dinner rather than to mock his son.
"It was gentle," Faure said, "but shows how Philip saw himself as different from Charles, his son sentimental while he was pragmatic."
Prince Charles's touching televised tribute at the weekend to "Dear Papa" demonstrated the warmth of his own feelings and respect for his father.
But as a blunt, sport-loving polyglot with a distinguished naval career behind him, the duke had found it hard to cope with a child whom he regarded as having been mollycoddled by nannies, according to Faure.
With the queen concentrating on "taking care of the kingdom", it had fallen to the duke to raise Prince Charles and his younger siblings.
He wanted, Faure says, to make his eldest son a man. "The child shows himself ready for such an adventure, arms himself with courage and tries to be like his father, a model of masculinity. But, for this, he must overcome many fears and anxieties."
Faure says that, in many ways, the pressure paid off. "As he got older, Charles began riding, took up the sports his father played, followed him into the Royal Navy.
"He began to trust himself and also earned some confidence from his father."
Not all of this development came naturally, the author says, since the young Prince Charles did not share the passion for horses of the queen and that of his sister, Princess Anne.
“He overcame fear to reassure Philip, to please him, to make him proud of him,” he writes, in his analysis of a complex relationship.
“He gets used to riding ponies, then hunting horses, participates in jumping competitions and becomes an avid polo player. He shoots grouse as it should be done in the English aristocracy, [goes] fly fishing and sailing, and follows his father’s footsteps into the Royal Navy.”
Faure praises Prince Charles’s “mastery and elegance” on the ski slopes of the Swiss Alps, where he showed skill and daring, and narrowly escaped an avalanche that engulfed his group off-piste in 1988, killing a close friend.
The biographer identifies art as another pursuit in which Prince Charles saw his father as a model, though Faure rates the duke’s oil paintings as superior to his son’s watercolours. He also developed a keen interest in the environment to match that of his father.
“Charles, pushed by his father, but also encouraged by him to move forward without fear on life’s path, arms himself with courage and ends up gaining confidence,” writes Faure.
“He finally opens up about himself and others, after a childhood marked by sadness, introversion and meditation before the beauties of nature and the large gardens of the family's castles.”
In boyhood, the author says, Prince Charles would infuriate his often curt, stern father. But Faure credits the duke with shaping his son “into an adult worthy of his rank, concerned about his usefulness and the fate of his subjects”.
Given his background as a globe-trotting reporter and his expertise on Latin America, a book on Britain’s royal family may seem a surprising project for Faure, now 70. His past works include histories of Cuba and Brazil, a study of the life of the Chilean dictator Augusto Pinochet, and a translation of a book on London by Boris Johnson, now Britain's prime minister.
But with the retreat from royal life, amid much bitterness, of the Duke and Duchess of Sussex and now the death of Prince Philip, Faure’s royal biography could hardly have been more effectively timed.
The book, which includes a chapter on the duke, the longest serving consort in British royal history, has so far been published only in France. It appeared little more than a week after the duchess’s controversial interview on US television with Oprah Winfrey on her unhappy life within the royal family.
"The French are fascinated by British royalty," Faure told The National during a stay in London where his grown-up children live and work. His daughter, Emilie, an art expert, was previously based in Dubai where she directed the Farjam Foundation, the UAE's first private museum.
“Sometimes the French are more monarchist than the British," he says. "They don’t want their own royal family back but we have what is sometimes called a republican monarchy, where the constitution gives the president so much more power than parliament.
"The level of attention, and the way different members of the family are regarded, goes through ups and downs according to events.
"My book on Pinochet was a lot more challenging, but when I tell people about this one on Charles, they are more interested.”