Human remains have been unearthed in a field behind a hamlet in the region.
Experts are studying the two skeletons, both male and thought to be 2,000 years old, which workmen found in a shared rough grave.
Examinations of the bodies, found near Newton Bewley, not far from Hartlepool, revealed that both men had been hacked to death. One, at least, had been beheaded.
Robin Daniels, of Teesside Archaeology Service, said it was rare for archaeologists to come across evidence of violent deaths.
He said the two men probably died during a raid on a well-defended chieftain's settlement.
A pathologist's report into one of the bodies said: "The penetrating wound to the front of the skull may have occurred first, and appears most likely to have been caused by a projectile rather than hand-to-hand fighting.
"This probably stunned him even if it did not render him unconscious, perhaps explaining the lack of any defence wounds on the arms and legs.
There were further stabbing and slicing wounds and, finally, two cuts with a sharp instrument that would have severed his neck.
The report said that injuries to both men indicated that they were soldiers killed in a battle or skirmish.
"Murder is another possibility, but execution seems unlikely in view of the number of injuries."
The skeletons were found at a settlement which survived from the Iron Age to the 5th Century, which was excavated in the path of a 96-mile long BP pipeline being laid between Teesside and Hull.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article