Artnews_ Thirty years ago, an anonymous buyer purchased an architectural watercolor of a crumbling chapel for £100 at a clearance sale of a Georgian mansion in Suffolk, England, reported the Telegraph. The painting turned out to be an early work by William Turner.

The buyer purchased the painting not knowing who the artist was and hung it in their dining room; inscribed on the back was the name ‘W Turner.’ The painting’s provenance prior to the Georgian mansion is unknown. The owner eventually verified the authorship by checking Tate’s Turner Bequest of thousands of paintings and sketches bequeathed to the nation when the artist died in 1851.

An earlier iteration of the piece was found in Turner’s South Wales sketchbook. There, they found a similar but less developed drawing of a chapel at St Davids Cathedral in Pembrokeshire. Turner sketched the landscape while on a tour of Wales in 1795 at age 20. Also noted in this sketchbook were his travel plans from Wells in Somerset and a visit to Picton Castle ahead of St Davids. He traveled, for instance, “36 miles and back” from Haverfordwest, writing, “no inn” and marked the locations of good inns with an ‘x.’

Turner had already been exhibiting at the Royal Academy since the age of 15, and his work was in great demand. Many of his subjects echoed his training as an architectural draughtsman.

He began touring around Britain in 1791 during the summer months. Sometimes these early sketches became finished pieces for paying clients.

Though Turner’s early topographical works don’t draw as much at auction as his later Swiss mountain views, which can garner millions, some of the earlier works like one of Caernarvon Castle in 1798 have sold for almost £500,000.

Local auctioneer Cheffins in Cambridge had Andrew Wilton, the first curator of the Clore Gallery for the Turner Collection at Tate Britain, assess the work. Wilton recognized it as a high finished Turner drawing, which would have been created from the sketch when the artist returned to his London studio. The signature and location notes, he confirmed, are in the artist’s handwriting.

Wilton believes the painting would have been a commission for a patron or friend of Turner, and it is the only known watercolor of the subject.

Since its origins remain unverified and the early landscape is uncharacteristic of Turner, the painting is expected to fetch only £20,000–£30,000 at auction with Cheffins on March 20.