The unusual relic was taken from the Thomas Dobrée Museum in the northwestern city of Nantes earlier this month, the BBC reported.

Two men were arrested on Saturday and led police to the buried treasure near the city of Saint Nazaire. Authorities had previously issued a public plea for the return of the heart, fearing it would be melted down for gold with the criminals unaware of its historic significance.

Breaking through a museum window to access the loot, the thieves escaped with precious items despite setting off an alarm. Though there had been suspicions that Breton nationalists might have been behind the theft, police said petty crime is the most likely motive, The Telegraph reported.

Schoolchildren look at the relic of the heart of the French queen Anne of Brittany at the castle of Blois, central France, as part of the commemoration of the 500th anniversary of her death, on March 21, 2014.GUILLAUME SOUVANT/AFP/GETTY IMAGES

Anne of Brittany died in 1514 aged just 36, though her short life was a busy one. The daughter of Francis II, Duke of Brittany, Anne became Duchess of the region at just 11 years old when he died in 1488. Her standing and reported wealth made Anne a sought-after wife, and she was first married to Holy Roman Emperor Maximilian I in 1490.

The marriage sparked a war between Brittany and Charles VIII, the king of France, who wanted to subjugate the neighboring region. Upon defeating Anne’s army, he forced her to agree to marry him instead. This was formalized in 1492 when Pope Innocent VIII annulled her marriage to Maximilian.

Charles died in 1498 when Anne was just 18. Though still young, her marriage to Charles produced seven children. However, only one child—Charles—lived longer than a month, but died aged 3.

This picture was taken on December 26, 2013, shows members of the Breton Wines’ Committee drinking a glass of Muscadet specially issued to commemorate the 500th anniversary of the death of Anne of Brittany next to her sculpture.FRANK PERRY/AFP/GETTY IMAGES

After the king’s death, Anne married Charles’s cousin Louis XII, who succeeded to the throne, making her the only woman in history to have been married to two French kings. She went through another nine pregnancies with Louis, giving birth to just two children that survived.

As a child, Anne was also briefly betrothed to the young Prince Edward of England. One of the “Princes in the Tower,” Edward disappeared with his brother Richard in mysterious circumstances while under the care of their uncle, the Duke of Gloucester, at the Tower of London. The Duke later crowned himself King Richard III.

Following tradition, Anne was buried alongside other French royals in the Saint-Denis Cathedral outside Paris. To show that her heart still belonged to Brittany, Anne requested it be removed and sent to her homeland upon her death. Her husband Louis was later buried alongside her.

During the French Revolution, the new government ordered the relic be sent to Paris to be melted down for gold but was instead kept safe in France’s national library. It was later sent back to Nantes and eventually found a home at the Thomas Dobrée Museum.