Human heads were dumped in open pits by head hunters in Roman times.Jeremy M Farmer/Flickr

Evidence showing that head hunters operated in London during Roman times has been uncovered at an archaeological dig site.

The discovery of 39 skulls has led experts to deduce some Romans would gather up the heads of executed enemies or dead gladiators and expose them in open pits for years.

According to the Guardian, the skulls were found at London Wall in 1988 but scientists only recently applied improved forensic techniques to them.

Rebecca Redfern, from the Museum of London's centre for human bioarchaeology, told the newspaper: "It is not a pretty picture. At least one of the skulls shows evidence of being chewed at by dogs, so it was still fleshed when it was lying in the open.

"They come from a peculiar area by the Walbrook stream, which was a site for burials and a centre of ritual activity – but also very much in use for more mundane pursuits. We have evidence of lots of shoe making, so you have to think of the cobbler working yards from these open pits, with the dog chewing away – really not nice.

Archaeologists show the skulls found at Liverpool. (Photo: ©Crossrail Ltd 2013)
The skulls were found as part of the Crossrail development project.Crossrail Ltd 2013

"We believe that some of the heads may be people who were killed in the amphitheatre. Decapitation was a way of finishing off gladiators, but not everyone who died in the Roman amphitheatre was a gladiator, it was where common criminals were executed, or sometimes for entertainment you'd give two of them swords and have them kill one another.

"Other heads may have been brought back by soldiers from skirmishes, probably on the Hadrian or Antonine walls – again, it would have taken weeks to bring them back, so not a nice process."

Published in the Journal of Archaeological Science, findings showed that almost all of the skulls were adult males. Most had scars, slash marks and multiple head wounds. One had a shattered cheek bone while others showed clear evidence of decapitation with a sword.

"Whether they died in the amphitheatre or in battle, decapitation with a sword is a very efficient way of ending a life – somebody very much wanted these people dead," Redfern said.

She also noted that they were not mounted on spikes – as depicted in many historical Hollywood films about Roman times – and that they probably were killed around the second century AD, a time of peace for Rome. "This is a glimpse into the very dark side of Roman life," she said.