Stone used as mounting block for years revealed to be Roman artefact

A stone used as a mounting block for an English stable has been revealed to be an ancient Roman artefact worth more than $26,000.

The stone was found in a garden rockery in Whiteparish, south-west of London, about 20 years ago, according to auctioneers Woolley and Wallis, who are handing the sale of the artefact.

The owner of the property used the stone as a mounting block for her horses for a decade before recently noticing the carvings on the side.

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An archaeologist found that the seemingly unassuming stone was a Roman-worked marble slab dating back to the second century CE.

It's believed to have been carved in Greece or Asia Minor - but is likely to have arrived in Britain long after the final collapse of the Roman Empire.

"Artefacts of this type often came into England as the result of Grand Tours in the late 18th and 19th century, when wealthy aristocrats would tour Europe learning about Classical art and culture," Woolley and Wallis antiquities specialist Will Hobbs said.

"We assume that is how it entered the UK, but what is a complete mystery is how it ended up in a domestic garden, and that's where we'd like the public's help."

The auctioneering house is seeking to establish the stone's more recent history.

It is to be sold at auction at a future date yet to be advised, with a pre-sale estimate of £10,000 to £15,000 ($17,576 to $26,365).