Hatpins may have fallen out of fashion, but these accessories were once quite popular among medieval kings. As Smithsonian reports, one particular gold hatpin that may have belonged to King Edward IV of England is hitting the auction block next week and could sell for upwards of $13,000.

And it was discovered entirely by chance. A woman was scanning a field near Horncastle, Lincolnshire with her metal detector in 2013 when she stumbled across this lucky find. The artifact has since been acquired by Duke’s Auctioneers in Dorchester, which plans to sell the pin as part of its Spring Fine Art sale on April 26.

Duke's Auctioneers

It’s believed that the hatpin belonged to Edward IV, whose two reigns lasted from 1461-1470 and 1471-1483, or a member of his royal court because it features the Sun-shaped motif he often used. This symbol stems from Edward’s observation of a meteorological phenomenon called a parhelion, or “Sun dog,” which makes it seem as if there are three Suns in the sky. Prior to being crowned king, Edward, then the Duke of York, witnessed this rare event in 1461 while fighting with the House of Lancaster in the Battle of Mortimer’s Cross.

“Edward, the Earl of March, told his men this was a sign from God representing the Holy Trinity and was proof that God would lead them to victory,” Duke’s writes in its description of the pin. “The Yorkists were victorious that day and Edward was proclaimed king a month later, after which he adopted the ‘Sunne in Splendour’ as his personal emblem.”

At the center of the sun is an amethyst—a jewel that was believed to protect the wearer in battle in medieval times. The color purple is also associated with royalty.

There’s also evidence that Edward IV and at least one other king wore hatpins during their reigns. A rendering of Edward IV from the National Portrait Gallery’s collection shows the king wearing the accessory, as does the below painting of a young Henry VII. In both cases, the hatpins are adorned with dangling strands of pearls.

A similar hatpin worn by a young Henry VIIDuke's Auctioneers

[h/t Smithsonian]