Experts examining an Iron Age skeleton found discovered buried beneath a medieval ship in Newport, south Wales, say it is "remarkably well preserved".
The bones date back to 170 BC
Tests on the bones, by forensic archaeologists at Lampeter University, mid Wales, have shown that they date back to 170 BC.
The bones were found three years ago, and the findings mean they are 1,500 years older than the 15th century ship.
The man is thought to have been about 5ft 8in tall and very muscular.
Dr Ros Coard, who examined the remains, said the body was probably buried quickly after his death.
This helped preserve the bones as natural bacteria was unable to take hold, she explained.
The skeleton, minus the head, was found underneath wooden struts supporting the ship as workers carried out an excavation of the orchestra pit of Newport's Riverfront Theatre and Arts Centre on 11 December 2002.
Dr Coard said: "The radiocarbon date places the Newport body at the late Iron Age.
"The Iron Age is known to be a time of ritual deposition into rivers and there are many archaeological examples of this.
"Interestingly from a British context, it is mostly the heads that are recovered. The Newport body is a rare example of body minus the head being recovered."
Dr Coard added: "It was also noted that the surviving bone is remarkably well preserved with none of the expected and usual decay due to putrefaction.
Workmen discovered the bones underneath the Newport Ship
"This suggests that he died and was buried very rapidly in an anaerobic environment where the natural bacteria were not able to take hold."
She said the collagen (the organic content of the bone) had also survived well, which made taking DNA a possibility in the future.
Archaeologists have concluded that the man's body may have been deliberately placed in the channel.
Meanwhile, the restoration team of the ship - expected eventually to be displayed in the new arts centre - could be more significant than the discovery of the Tudor ship, the Mary Rose.
Kate Hunter, the project leader for Newport Council, expects the conservation programme of recording the timbers and restoring the ship to take between 10 and 15 years.