The cool, waterlogged conditions of Northern European bogs (a type of wetland) create low-oxygen, highly acidic environments ideal for body preservation.
Hundreds of bog bodies have been uncovered in the region but many have shriveled down to mostly skeletons and tend to be closer to 2,000 years old.
A bog body is a human corpse that has been naturally mummified within a peat bog.
A resident of central Ireland's County Laois came across the well-preserved "Cashel Man" - named for the bog he was found in - while milling for peat moss, which is used for a variety of farm purposes, 'LiveScience' reported.
More From This Section
"All that was visible to start with was a pair of legs below the knees, and a torso," Eamonn Kelly, an archaeologist at the National Museum and lead excavator of the project, wrote in the Irish journal Ossory, Laois, and Leinster.
"The body appeared to be naked. Later, it was possible to work out that the torso had been damaged by the milling machine, which also removed the head, neck and left arm," Kelly said.
The team calculated the age of the body using radiometric carbon dating and found the body was roughly 4,000 years old.
The team conducted computed tomography (CT) scans of the body after the dig, and found that the young man's arm and spine had been broken multiple times, seemingly from sharp blows before his death.
The researchers also found cuts along the man's back that looked like ax wounds. They uncovered axes capable of producing such wounds within the vicinity of the site.
The team concluded that the young man had been killed in a ritual sacrifice, a practice commonly known in later eras, but not well documented in the Early Bronze Age of 2000 BC, about the time this bog body would've lived.