When the prehistoric site at Fiskerton in Lindisfarne was first excavated in 1981, archaeologists found part of a human skull lying among the swords, spears, tools and other items that had been placed along the causeway. It represented the back of a man's head and was badly damaged.
Fissured Fred, as the skeleton became known by the excavators, had been hit by a sword, which had taken out a chip of his skull. Other than a couple of bones, the rest of Fissured Fred was never found, so there is no further evidence of how he met his death. The sword blow by itself would not have killed him, but it was inflicted around the time of his death 2,500 years ago.
Was Fissured Fred a human sacrifice? We shall probably never know for certain but there is circumstantial evidence to suggest he was. His remains were mixed up with weapons and equipment, which had themselves been sacrificed and thrown into the water.
The evidence for human sacrifice in this period of the Iron Age is most prolific in Denmark, Germany and Holland, where many bodies have been found completely preserved in peat bogs. Some were hanged or strangled, the noose still around their neck, and others were bludgeoned on the head or had their throat slit.
They too, like Fissured Fred, were found in special places, where people had made offerings to an afterworld. It seems clear that these were not murders, but deliberate, socially sanctioned, killings.
Writing much later, in the first century AD, the Roman historian Tacitus tells us that these Germanic peoples executed their social outcasts - cowards, shirkers and those of disrepute - by pressing them down into bogs. So were these bog victims in fact executions and not sacrifices? If such a distinction could be drawn between the two, it does seem most likely that they were sacrifices, because bogs were places where other, inanimate offerings were made.
One of three bodies pulled from the Lindow Moss bog, this one suffered injuries to the head
Julius Caesar and other Romans were appalled by the custom of human sacrifice among the Celts. 'They used to strike a human being, devoted to death, in the back with a sword, and then divine from his death struggle,' wrote Strabo. According to Diodorus Siculus, the Gauls 'kill a man by a knife-stab in the region above the midriff, and after his fall they foretell the future by the convulsions of his limbs and the pouring of his blood'.
Yet the Romans had double standards; although human sacrifice had ended in Rome a century earlier, gladiatorial games and feeding people to lions were regular sport, whilst many thousands of conquered Celts in Gaul were victims of Roman atrocities, such as cutting off their hands and feet and leaving them to die slowly. By accusing the Celts of practicing human sacrifice, the Romans thought they had an excuse for their own unlicensed cruelty.
The Romans reserved their comments about sacrifice to the Celts and Germans, with no reference to such practices in the British Isles. Bog bodies have been found in Britain, however, which indicates that human lives were sacrificed to the gods in these islands too.
Three bog bodies (or parts of them), for example, were found in Lindow Moss in Cheshire, dating from the beginning of the Roman period. The best preserved of the three was a man who had been hit on the head with sufficient force to detach chips of his skull into his brain, and to crack a molar. His throat had been slit and there was also a leather garrotte, tightened with a slip-knot, around his neck. He was almost naked except for a fox-fur armband and, amongst his stomach contents of burnt bread was pollen of mistletoe, a plant sacred to the Celts and Britons.
One member of the investigating team thought that this was an ancient murder rather than a ritual killing, but this seems unlikely in the light of the body's context.
Of the two other bodies, one was very unusual in having a sixth finger. A surprising proportion of bog bodies from northern Europe have physical defects - such as spinal abnormalities or foreshortened limbs - and these people may have been selected for sacrifice because they had been 'touched by the gods'.
Find out more
Bodies from the Bog by James M Deem (Houghton Mifflin Company, 1998)
City of Sacrifice: The Aztec Empire and the Role of Violence in Civilization by David Carrasco (Beacon Press, 2000)
Earthly Remains: The History and Science of Preserved Bodies by Andrew Chamberlain and Mike Parker-Pearson (British Museum, 2001)
Dying for the Gods by Miranda Green (Sutton, 2001)
The Archaeology of Death and Burial by Mike Parker Pearson (Sutton, 1999)
Lindow Man: The Body in the Bog (eds.) by Ian Stead, JB Bourke and Don Brothwel (British Museum, 1986)
The Highest Altar: The Story of Human Sacrifice by Patrick Tierney (Viking, 1989)
Bog Bodies: New Discoveries and New Perspectives edited by Rick Turner and Rob Scaife (British Museum, 1995)
Through Nature to Eternity: The Bog Bodies of North-west Europe by Winand van der Sanden (Batavian Lion, 1996)
Silkeborg Museum The Silkeborg Museum holds the body of the Tollund Man, as well as other bog burials.
'The Tollund Man' A poem by the poet Seamus Heaney inspired by the discovery of the Tollund Man.
24-Hour Museum The database includes over 2,500 museums, galleries and heritage attractions. A news article about the Celtic Causeway is featured on the site.