A barrel full of butter, estimated to be around 3,000 years old, was found in a peat bog in County Kildare in Ireland.

Two peat workers, John Fitzharris and Martin Lane, stumbled upon an oak barrel full of butter when they noticed a white streak in an Irish bog in Gilltow, County Kildare.

The Irishmen knelt down to examine it, and saw it was a trunk filled with butter weighing almost 77 pounds

The trunk had a large split down its side caused by the butter expanding over time.

Archaeologists say the barrel of butter, which was lidded and 3 feet long, is from the Iron Age and is approximately 3,000 years old.

Pádraig Clancy of Ireland's National Museum said: “It's rare to find a barrel as intact as that.

“Especially with the lid intact, and attached. It's a really fine example.”

The men who discovered the butter put the barrel in the cab of their tractor and eventually handed it over to the National Museum of Ireland.

The staff of the Irish Conservation Department is drying the butter out, and once dry, will soak it in a wax-like solution to preserve it.

The aged butter has turned white and transformed into adipocere, which is animal fat, the same substance found on well-preserved bodies of people or animals found in the bog.

It is now being dried out by the Conservation Department. Once dry it will be soaked in a wax-like solution which preserves it.

Experts say the butter was put in the bog for practical reasons.

“There are accounts dating back to the 1850's with people used to wash their cattle once a year in the bog and then put some butter back into the bog. It was piseogary,” Clancy said. The butter was usually “stolen by the following week.”

Clancy explained: “It's open to interpretation, but we're inclined to think that 3,000 years ago they were just storing it.”

It is thought that the butter was the harvest of a community rather than an individual farmer.

Various artifacts have been discovered in bogs in Kildare, including spear heads, pottery and bodies.