A medieval warrior whose face was split open in one of Europe's most savage battles has been brought back to life in a stunning recreation, 660 years after his gruesome death.

Experts reconstructed the fighter's visage after his skull was recovered from a mass grave outside Visby on the Swedish island of Gotland.

It was there in 1361 that a Danish force of some 2,500 men, many of them experienced mercenaries, perpetrated a massacre.

They faced a rural militia of roughly 2,000 poorly-armed peasants – at least a third of whom were minors or the elderly, excavations suggest.

In the slaughter that followed, the defenders suffered some 1,800 dead.

Among them was the warrior, whose mouth was smashed by an axe, with additional wounds above his left eye and on the left cheek bone probably caused by a pole weapon.

Now Brazilian graphics expert Cicero Moraes has brought his features to life by importing his skull into a digital interface.

He said: 'Once the skull was ready, a series of soft tissue thickness markers were spread across the skull.

'These markers, roughly speaking, indicate the skin boundaries in some regions of the face.

'To complement the data, we imported a CT scan of a living donor and deformed the bones and soft tissue from the CT scan to match the face being approximated.

'With the basic face defined, we finalised the approximation and generated the most scientific image, in shades of gray, with eyes closed and without hair.'

The skull itself yields an incomplete set of data, so some aspects – like the size of the nose, mouth and eyes – are projections based on statistical data.

Meanwhile, matters like hair and skin tone are subjective.

But the end result is an approximation of what the warrior would have looked like at his time of death.

Whether it was blow from axe that proved fatal remains unknown.

Mr Moraes said: 'It is difficult to estimate this with the skull alone.

'But surely such an injury would not be an easy thing to treat, considering the year and the reality at the time it was inflicted.'

For Mr Moraes, the images bring home the reality of war.

'These images are quite impactful,' he said.

'Today we have several conflicts happening in the world and we usually observe the scenes from afar, having no idea what happens to the combatants.

'Imagine how it is for those who receive such violence.'

After the battle, the citizens of Visby – the island's capital – surrendered to avoid further bloodshed. The victorious King Valdemar IV was paid a heavy ransom and claimed the island as part of his kingdom.

Both Sweden and Denmark continued to claim the island until the Second Treaty of Brömsebro was signed in 1645, following Denmark's defeat in the Torstenson War.

Five mass graves were ultimately found outside Visby's walls, with the first archaeological excavations in 1905 revealing many of the dead were buried in their armour.

Mr Moraes completed his reconstruction using a three-dimensional model of the skull shared by the Swedish History Museum in Stockholm.

He published his study in the 3D computer graphics journal OrtogOnLineMag.