Story behind brooch worn by former Queen of Denmark, Margrethe II

Called the Ruby Horseshoe, the gift from her father has marked both her first and final day on the throne

Denmark's Queen Margrethe II signed a declaration of abdication on Sunday, wearing the Ruby Horseshoe brooch. EPA

Queen Margrethe II of Denmark discreetly bookmarked the end of her decades-long reign through a simple brooch.

Called the Ruby Horseshoe brooch, it was given to her on June 5, 1953, by her father King Frederik IX, to mark her becoming the heir apparent to the Danish throne.

She became his heir only after a referendum to change Danish law. As the king only had daughters, Margrethe being the oldest of three, a change in law was required to enable queens to rule in their own right.

To mark this historic moment, as well as the start of Margrethe's official public life, the king presented her with the brooch. The jewel is set with 11 pinkish-red rubies and flanked by smaller white diamonds, echoing the colours of the Danish flag. The horseshoe shape, meanwhile, has long been considered a symbol of good luck.

Posing for a family photo on that day, Margrethe, 13, can be seen wearing the brooch pinned to the neck of her dress.

Princess Margrethe was proclaimed queen in 1972, an occasion on which she wore the Ruby Horseshoe brooch. Getty Images

On January 15, 1972, Margrethe wore the brooch once again, as she was proclaimed queen following the death of her father the day before.

Dressed in full mourning black, the young monarch chose to wear the brooch at the throat of her dress as the prime minister announced her as queen. Denmark does not crown its monarchs, instead making a public proclamation of their ascension.

The queen wore the brooch again in 2012 to mark her Ruby Jubilee. The piece of jewellery commemorated not only her long reign, but also the four decades since the death of her father.

Clearly of great personal significance to the royal, she has also worn the jewel for important family occasions, including the birth of her grandchildren.

When Margrethe declared in a live television broadcast on New Year's Eve that she would be stepping aside to allow her son to be crowned, she took the world by surprise. And as she signed the instrument of abdication at Christiansborg Palace on Sunday, to officially pass the throne to her son, she was once again seen wearing the Ruby Horseshoe brooch.

As one of Europe’s longest-serving monarchs, it is fitting that a gift from her father – now woven into Danish history – has marked both her first and final day as queen.