The function of Neolithic copper daggers finally elucidated?

In the archaeological tradition, daggers from the Chalcolithic period (period of prehistory characterized by the beginning of the use of copper) are considered symbols of male power. A recent study counterbalances this idea by showing that these blades were used in a wide variety of ways, particularly in the cutting of carcasses.

Chalcolithic and Bronze Age daggers were not merely badges of male power, as the archaeological tradition assumed.

Copper-alloy blades were discovered across much of Europe during the Chalcolithic, and later into the Bronze Age. Despite a great diversity of exhumed blades, studies are rare on the function of these metal artifacts. A gap partly filled thanks to the microscopic analysis, by a team of archaeologists, of ten daggers discovered in northern Italy. The study, published in Scientific Reports on April 12, 2022, demonstrates a multifunctional use of these daggers, especially in butchering animals. According to Andrea Dolfini, an archaeologist at Newcastle University who participated in the study, "Organic residue analysis is commonly applied to ceramic, stone and shell artefacts. We have therefore modified the method to be able to apply it to copper alloys ."

An artifact associated with warriors

These daggers appeared simultaneously, in the 4 ^th millennium before our era, in a large part of Europe and on the Italian peninsula. Flint was gradually abandoned in favor of copper alloys, with arsenic or tin. It is also the period of strong commercial activity, with exchanges of artefacts throughout Europe during the Bronze Age. The function of these daggers has long been a subject of debate among archaeologists. Some interpreted them as symbolic accessories, or objects used for slaughter rituals. Frequent finds of daggers in warrior tombs have led archaeologists to believe that they were non-functional insignia, symbols of male power. Also, the weakness of the copper alloy meant that these daggers could not be strong enough as close range weapons.

These artefacts were discovered between 2016 and 2017 at the site of Pragatto (Italy), which is part of the Terramare system (name given to the archaeological culture specific to the Bronze Age), a site of prehistoric settlement in the valley of the Po, occupied from -1650 to -1200 BC. It is famous for its remains of square villages of between 1 and 20 hectares, once established near rivers and surrounded by palisades. In addition, part of the village bears traces of fire, which would have allowed the preservation of a number of elements to the present day:nine burnt houses, a waste pit, an animal enclosure and 150 rooms furniture in copper alloy, including 55 daggers.

Organic residue on the blades

Examination of the 55 daggers shows that they were in prolonged use, with traces of repair and damage to the edges of the blade. Also, the very small size of some daggers requires regular sharpening until they are no longer usable. The researchers assumed that the wear marks were caused by repeated contact with soft materials such as animal or plant tissue.

The 10 daggers carrying the most of these residues were selected to be analyzed in depth, thanks to microscopic observation and SEM/EDX analysis. They come in varying lengths and the majority have the rivets attached to an organic wooden handle. Observation under a scanning microscope thus showed organic residues accumulated along the blades and at the base of the handle, as well as hydroxyapatite, a calcium phosphate formed on the blade by the remains of crushed bones. Traces of collagen, bone, muscle and tendon fibers were found, but also of plants, including starch from triticeae , a family of cereals including wheat, barley and rye.

These organic tissues have been preserved thanks to metal compounds that limit bacterial and enzymatic activity. The composition of the soil, rich in acids and tannins like peat bogs, also allowed better conservation of protein organic matter.

Multiple uses

These recent analyzes demonstrate that daggers made of copper alloy were much more functional than this, especially in the treatment of animal or plant carcasses. A use that fits with the context of Pragatto where breeding was very popular. The effectiveness of these blades in cutting has been confirmed in experiments on pig and deer remains, green wood and wheat, thanks to replicas in alloys of similar metals. Also, 7-10 days later, the appearance of orange/green colored oxidation, caused by contact with flesh, was similar to the oxidation spotted on Pragatto's daggers.

But Andrea Dolfini does not exclude the first proposals. "It's a safe bet that these metal daggers, and some flint, were also used as weapons or as signifiers of male identity, perhaps in connection with clan status. Chalcolithic and at the beginning of the Bronze Age, they were often deposited in the graves of warriors, very predominantly male ." While these results are significant, they remain speculative due to the rarity of this type of study of daggers from this era. "The method can be applied to any copper alloy from around the world. integer , continues the researcher. It can reveal a wide variety of organic animal or plant residues. Further research may allow the isolation of other types of residues, eg fats, starches, hemoglobin from human or animal blood. But of course we don't yet know how this line of research will develop in the future. "