Mary was then made to convert from her Presbyterian faith to the Danish Lutheran Church as well as agree to give up her rights to any future children she and Frederik may have in the future in case they divorced.
Then the biggest, and perhaps most obvious, sacrifice was made - Mary, the Aussie girl who found her very own fairytale, was made to relinquish her Australian AND British citizenship (which was a result of her Scottish-born parents) in order to become a Danish citizen.
Usually, it is a nine-year process for non-Danish-born individuals to attain citizenship, gained through continual residency.
But given the special circumstances surrounding the newest member of the Danish monarchy, the Danish parliament passed 'Mary's Law', giving Mary Danish citizenship through her marriage to the future King of Denmark.
In the almost 20 years since marrying, Mary has thrown herself into her royal duties, Danish quickly becoming her preferred tongue.
But that doesn't mean she has forgotten her Aussie roots, making numerous official and unofficial visits down under over the years!
During the 2023 FIFA Women's World Cup, Mary hinted at still holding a place for her homeland in her heart as Australia and Denmark faced off in high stakes, high-reward game.
"We cheer from "Top Over" and all the way "Down Under," when the match against Australia starts at the World Cup. Come on, Denmark ⚽️," The Crown Prince Couple shared on the official Danish royal house Instagram account.
The accompanying image was of Mary with her beloved bordie collie Grace who posed with a soccer ball in the colour of the Matildas, as well as Princess Mary with the colours of the Danish flag painted upon her face.
Whilst the image did little to confirm where Mary's true loyalties lie, her inclusion of the Aussie colours at all was a sweet nod to her roots.
The morning after the game (in which the Matildas scored a victory, knocking out Denmark), Australian Prime Minister Anthony Albanese weighed in on a debate that had been raging in the leadup to the game.
"I think she's done that already, mate," he said when asked whether Mary's lack of obvious allegiance to the Matildas was enough to have her citizenship revoked.
"I think that's how you get to be a princess," he joked.