A builder in the Polish town of Hrubieszów was in for a surprise when he discovered a sword while draining a bog filled with peat.

The sword is incredibly well-preserved, and is believed to date back to the late 13th or mid-14th century.

While the sword's owner remains unknown, researchers believe that a cross in the shape of a shield on the back of the sword would have served as the blacksmith's brand mark.

One theory is that it belonged to an unlucky medieval knight who may have fallen into or lost his sword in a bog filled with peat 600 years ago.

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A builder in the Polish town of Hrubieszów was in for a surprise when he discovered a sword while draining a bog filled with peat

THE SWORD The sword is almost entirely preserved, aside from the hilt. It is around 1.2 metres (four-foot) long, and researchers estimate that it weighed around three pounds at the time it was made. A cross in the shape of a shield on the back of the sword would have served as the blacksmith's brand mark. Advertisement

The sword is almost entirely preserved, aside from the hilt.

It has since been donated to the local Stanisław Staszic Museum.

Speaking to science journal PAP, Bartłomiej Bartecki, director of the museum, said that the sword is a 'unique find in the region' but would have been a typical weapon for knights 600 years ago.

Researchers from the museum estimate that the sword, which is around 1.2 metres long, weighed about three pounds at the time it was made.

The sword is almost entirely preserved, aside from the hilt. It is around 1.2 metres long, and researchers estimate that it weighed around three pounds at the time it was made

Speaking to National Geographic, Mr Bartecki said that a cross in the shape of a shield on the back of the sword would have served as the blacksmith's brand mark.

He said: 'It's kind of a medieval company name.'

The sword has now been sent to Warsaw for analysis in the hopes of revealing more about the identity of its owner.

Experts believe that a cross in the shape of a shield on the back of the sword would have served as the blacksmith's brand mark

The sword was found in a bog in the Polish town of Hrubieszów. After analysis, it will return to Hrubieszów to go on display

It will then be returned to Hrubieszow to go on display in Septemeber.

While the location of the bog has not been revealed to prevent looting, archaeologists plan to return there to see if it heralds any other artefacts, or even bones.