Earliest Brain in Britain found in York

Richard Hall, Director of Archaeology, York Archaeological Trust

Since 2003 York Archaeological Trust has been undertaking archaeological investigations on the Heslington East Campus development at the University of York. The site lies some 3km to the south-east of York city centre, c.700m to the east of Heslington village. Desk-top study, fieldwalking, geophysical prospection and trial trenching culminated in 2007-8 with the excavation of just over 8 hectares. This exposed a multi-phase prehistoric landscape incorporating a field system with round houses and other features, including a water hole. centred chronologically on the Iron Age, although traces of earlier prehistoric activity of Mesolithic, Neolithic and Bronze Age date were also found.

One of the items recovered was a human skull, found face down with its mandible and the first two vertebrae, in one of the many pits on the site. Although unusual, this was not thought at the time of discovery to be of mind-boggling importance. The excavator lifted the skull in some of the surrounding damp soil and used padded bags to pack this block carefully into a tub for transport. It was then sent for processing in the usual manner.

In the Finds Laboratory Rachel Cubitt, one of YAT’s Finds Officers, carefully removed the ensemble from the tub and was able to extract the skull, mandible and vertebrae from the soil block. During this process she felt something inside the skull move. Initially, she assumed it to be a lump of mud that had become detached from the inside of the skull as it dried out. Peering though the hole at the base of the skull to investigate, she saw instead a quantity of bright yellow spongy material and, with great presence of mind, realised it might be brain material.

Expert opinion was sought from Dr Sonia O’Connor, of Bradford University, who has experience of investigating human brain material from archaeological sites. X-radiography, coupled with the use of an endoscope to get a better look inside the skull, allowed her to conclude that this was indeed brain residue. Radiography revealed at least three endocranial masses with apparently differing gross morphology. One of these masses appears to show the neural folds of a shrunken lobe of the cerebrum. A sample of the material in the skull was removed and examination of this under low magnification revealed that it has a texture, resilience and convoluted structure similar to remains of brain retrieved from medieval burials in similarly wet deposits at the Hull Magistrates Courts site in the 1990s.

The skull was taken to York Hospital where it was examined using computer tomography (CT) and magnetic resonance (MR) imaging by David King, Consultant Radiologist and Philip Duffey, Consultant Neurologist (Fig 1). They concluded that the resultant images revealed sufficient detail of the external and internal morphology to confirm that this was indeed the shrunken and distorted remains of what had once been the brain.

Radiocarbon dating subsequently indicates that the skull dates to the sixth century BC. So the skull contains the oldest surviving human brain material in Britain. It is a remarkable discovery. Such finds are rarely reported, and this may be the earliest known example of preserved brain material from Europe, and one of the earliest in the world. It is a valuable example of an exceptional form of archaeological preservation; the study and understanding of this find is of international significance.

From observations of brain tissue in recently deceased humans, it is known that the brain is very quick to putrefy to liquid. Therefore, the survival of recognisable brain morphology, e.g. neural folds, would seem to indicate that only a very brief time (hours rather than days) elapsed between death and burial in an environment that encouraged the development of a persistent alteration product.

The research project is designed to improve our understanding of why brains survive and what that could indicate about funerary practices or the individuals to whom they belonged. Furthermore, this should allow us to predict more accurately the burial conditions in which brains might be found, improving the rate of recovery on future excavations. It is possible that these survivals are much more common than we realise and, therefore, that an important class of evidence is being neglected.

A wide ranging programme of research has been identified; and, thanks to funding from the University of York, it has been possible to bring together a group of eminent specialists, including many from the University of York, who will examine the brain material from their own particular scientific perspectives.

While the research planning was underway, the skull, still containing the brain material, had been kept in appropriately cool conditions in the YAT Conservation Laboratory. Two questions continually exercised our minds. Firstly, having been removed from the soil conditions in which it had survived for the last two thousand or more years, was the brain material now deteriorating? And, secondly, could we successfully remove the brain material from the skull?

The assistance of York Hospital’s mortuary was the initial key to answering these questions. Having finished their round of necessary hospital work for the day, the staff there undertook to trepan the skull in order to allow removal of the brain, just as they might have to do when conducting a post-mortem examination. So, after extensive digital and other recording, the skull was put into expert hands and the top of the cranium was removed. Two millennia in the moist ground had softened the bone, and the cut was made ‘as if through cheese’. At this point it was possible to see the brain residues for the first time; it was an enormous relief to see that there was no obvious sign of deterioration.

The next critical stage in the operation took place the following day at the University of York. Surrounded by many of the specialists who will work on the material, Sonia O’Connor began the extremely delicate task of removing the surviving brain residue. Fortunately, the residue was in the form of coherent but reasonably sized individual ‘lumps’ which could be removed from the skull and the soil matrix within it without too much difficulty. Soon a number of these muddy ‘lumps’ were free of the skull. Then it was time to attempt to remove the muddy covering from the brain residues. Careful cleaning and gentle washing combined then to reveal the truly exceptional condition of preservation, as neural folds on the surface of the brain became clearly recognisable. A certain quiet jubilation buzzed around the room, as it became obvious that future research options remained open thanks to this extraordinary preservation.

Over the last few months a series of analyses and recording procedures has been underway in laboratories in York, Bradford, Hull, Manchester and London, to extract every possible ounce of information about the individual in life, his or her death, and what happened to the skull after death to allow this remarkable survival of Britain’s oldest brain. YAT hopes to have these results drawn together within the next six months.