A painting of the interior of a church from 17th century Germany is valued at £100,000-150,000 ($154,190-231,285).
It's set to headline Sotheby's Old Master day sale in London on July 9.
The painting is attributed to Anton Gunther Geringh
The lot bears the initials AG, which are believed to belong to Anton Gunther Gheringh.
This is up for debate though, as Sotheby's explains "very little is known about Gheringh's formative years.
"He is thought to have been of German extraction, but his exact place and date of birth remain unknown, and where he underwent his artistic training equally so.
"The church itself provides no clue, for the architecture is evidently imaginary, and the tombs, monuments and coats-of-arms upon them all equally fanciful."
Other attributions, including to Abraham Mathysz van Gherwen have been made, but are inconclusive. It may ultimately prove impossible to identify the painter.
Isack van Ostade's Winter Landscape with Figures on Frozen River carries an identical estimate of £100,000-150,000 ($154,190-231,285).
Ostade (1621-1649) was a Dutch artist well known for his winter landscapes, which he painted from 1641 until his death at the age of 28.
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