"It's a modest social background, but it's also a leftist background," said Nalle. "The heir to the throne is marrying someone who not only was a commoner but someone from social circumstances where 50 years ago they would have been killing each other."
One thing that hasn't changed for the Spanish royals, however, is the security concern. When Felipe's great-grandmother, Princess Ena of Battenberg, married King Alfonso XIII on May 31, 1906, an anarchist hurled a bomb at the royal coach. The newlyweds escaped injury, but many others weren't so lucky.
This time, they're taking no chances. When Felipe and Letizia leave the cathedral, they'll skip the traditional horse-drawn coach in favor of an armored Rolls-Royce.
A Prince Walks Into a Bar …
In Copenhagen, security is also a concern.
Crown Prince Frederik and his Australian bride will be able to wave to their future subjects from a horse-drawn carriage after the ceremony, but well-wishers have been asked not to throw flowers, for fear they may be mistaken for a bomb.
The Danish people had long expected their prince, who turns 36 this month, to marry a foreigner, said the Copenhagen Post's Engmann.
The royal family must strike a delicate balance, she said — "not too far removed but not too accessible." If Frederik were to marry "some girl from the suburbs," many Danes would know her, and the royal mystique would be lost, Engmann said. And since the marriage market isn't exactly teeming with young women of royal blood, a foreigner would be the next best choice.
The prince met Donaldson, 32, in a bar while in Sydney for the 2000 Olympics. Her parents had immigrated to Tasmania from Scotland; her father is a math professor. Before her engagement, the Danish Embassy in Australia reportedly was instructed to conduct a discreet investigation to make sure there were no skeletons in the prospective fiancée's cupboard.
While the Scandinavian royals are much more relaxed than Britain's House of Windsor, the Danish monarchy still has some pretty stringent standards. After all, the same family has been sitting on the throne since the Viking age.
"Denmark has the oldest monarchy in Europe," said Engmann. "It's a rallying point for the whole country."
In Norway, for instance, where the current monarchy was established in 1905, the royals are a little more free-spirited. Before her 2001 marriage to Crown Prince Haakon, Crown Princess Mette-Marit was a single mother with a young son from a previous relationship with a man who had been convicted of a drug offense.
"That sort of thing would never be accepted in the Danish royal family," said Engmann.
The Danes, said Engmann, want a princess who has no embarrassing past and can be molded into a representative for the nation. On that front, Donaldson still has to prove herself — first and foremost, by learning to speak Danish fluently.
A Royal Role Model
In that, said Engmann, she has a fine example in her new sister-in-law, Princess Alexandra. Born in Hong Kong to a half-Chinese, half-British father and an Austrian mother, Alexandra Manley married Prince Joachim, Frederik's younger brother, in 1995.
"She's very popular," said Engmann.
Alexandra, the first member of a European royal house to be of Asian extraction, was quickly welcomed as a representative of her new nation.
"The most important thing she did was to learn Danish very quickly," said Engmann.
A former stockbroker, Alexandra was quick to adapt to her new role.
"Alexandra gave the people something they were craving, a young princess wearing a big hat and gloves and giving the royal wave," said Engmann.
Mary Donaldson and Letizia Ortiz, as they adjust to their new positions, will find themselves graded not on royal pedigree, but on job performance.
"Now," said Engmann, "it's more a matter of proving through your actions that you're worthy of becoming a royal."