Skeletons discovered at a mass grave at a medieval hospital are believed to date from the Battle of Lewes.
Four of them have now been tested by experts who revealed the dead men suffered from multiple wounds to the head inflicted with a sword.
Last year initial tests had revealed one of the skeletons dated from around the time of the Battle of Hastings, but this has since been disproved.
The exciting news was revealed in the TV show Medieval Dead which was screened on Yesterday on April 13.
History buffs can catch up with the show online where they can discover more about the investigation.
The film also explores Malling Down, the site of a mass grave discovered in the 1970s.
It is thought this was the site of a mass public execution in the Saxon era of Viking raiders.
County archaeologist for East Sussex County Council Casper Johnson said: “We now understand far more about these very important sites than we did before.
“This has been a highly significant review of Lewes archaeology.
“It has shown the value of professional team work, of double-checking anomalies and, most importantly, of keeping an open mind.”
The review was led by Sussex Archaeological Society and the County Archaeology Service for East Sussex.
It looked at the medieval hospital of St Nicholas which was run by Lewes Priory’s monks and the site at Malling Down.
Skeleton 180, from the medieval hospital, had been carbon dated and appeared to have died during the Norman Conquest.
But specialists at the University of Glasgow dated skeleton 180 as well as another 12 skeletons from the cemetery using more indepth methods.
Specialists, including experts from the University of York, discovered all four skeletons in the cemetery which died violently as a result of sword blows to the head were killed during the 13th century and may have died during the Battle of Lewes.
Assistant county archaeologist Greg Chuter added: “Evidence suggests this was the site of a mass public execution in the late Saxon period.
“These could have been local criminals but, given the burials, were all well-built young men executed at the same time and the manner of their deaths, the exciting possibility exists that these could have been Viking raiders, who are recorded in the Saxon Chronicles as marauding the Sussex coast at this period.”
Edwina Livesy from Sussex Archaeological Society, who co-ordinated the 2014 Battle of Lewes celebrations, said: “This is one of the most interesting projects I have worked on and we have benefitted hugely from having a first rate team of people looking into this.
“It is of massive importance to Lewes archaeology and a significant highlight of the Battle of Lewes commemorations. I’d like to thank Lewes Town Council and the South Downs National Park Authority for funding this project - it’s something for which Lewes can be justifiably proud.”