Thirteen years ago, an 11-year-old boy in England discovered an elaborate engraving at a dump site. Unaware of its value, he stored it in his home for over a decade before making the decision to have it appraised by an auction house this year. The auction house’s director, Jim Spencer, immediately recognized the engraving as something special.

Experts at the British Museum confirmed that the piece was a 500-year-old print of a woodcut engraving by the legendary German Renaissance artist Albrecht Dürer, titled Knight, Death and the Devil (1513). Renowned for its intricate detail and craftsmanship, the piece is one of Dürer’s three “master prints.”

The engraving has been put up for auction with a conservative guiding price of £10,000 to £20,000. However, experts believe it could sell for much more.