His mother, Queen Elizabeth II, was crowned in 1953 with huge fanfare and national excitement aged just 25, and in the ensuing years earned the love and respect of millions worldwide.
But after 73 years as her understudy, Charles's reign risks paling in comparison.
"It will be very difficult for him in terms of following the queen," said Robert Hazell, founder of the Constitution Unit at University College London.
"The monarchy is likely to go through, I think, some testing times," he told AFP.
For decades, Charles was defined by his marriage in 1981 to Diana, the mother of their two sons William and Harry. The union began as a fairy tale before collapsing very publicly, with both sides admitting infidelity.
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After her death in a car crash in Paris in 1997, there was an outpouring of public grief and anger -- much of it directed at Charles.
But there has been a gradual acceptance of his relationship with his long-term lover Camilla Parker Bowles, whom he married in 2005.
Charles has also been known for his outspoken comments on topics from farming to modernist architecture, and often faced mockery and accusations of meddling, even if his environmental concerns have now become mainstream.
Huge crowds turned up at Buckingham Palace Friday to see Charles arrive, although military veteran Michael Hull, 82, complained: "I don't like a ruler that talks to trees."