Iron knives from Denmark - 500 BC - AD 1500

Iron knives are well suited to historical analysis of the production, distribution and consumption of iron. With the knives as one’s point of departure the work can encompass a long, continuous chronological development, for knives were forged throughout the two thousand years when the farmers produced iron from the Danish bog ore. So far metallurgical analyses have been published of two knives from Hagestad in Scania, eight knives from Haithabu/Hedeby, ten knives from Illerup Ådal, two knives from Idskov and one knife from Vogn. In addition two iron knives from Hedegård, one from Hørup and eight knives of Technological Knife Types I and II have been published in summary form. The present study comprises the metallurgical analysis of 62 knives, 14 of which have been dated to the Early Iron Age (c. 100 BC-200 AD) and 47 to the Late Iron Age and Viking Age (c. 200-1000 AD). It is evident from the analyses that the Danish forging technology was chronologically, functionally and perhaps also regionally determined. One can establish six technological knife types: six different ways in which the smiths combined pure iron and carbon iron when they forged knives.

Knife forged from one piece of iron containing less than
 0.35% carbon

Knives forged from one piece of iron

Knives forged from one (or more) pieces of iron that contain less than 0.35% carbon and where no welded joint has been laid along the centre line of the knife are defined as Technological Knife Type I. In Denmark knives were forged in this way throughout the two thousand years when the farmers produced iron from Danish bog ore. Out of 14 iron knives from the Pre-Roman and Early Roman Iron Age found in graves and analysed, 12 (= 85%) are of Technological Knife Type I. This knife type is not quite as frequent in the graves from the Late Iron Age and Viking Age, making up 7 out of 36 (= 19%). The slag inclusions in the iron in four Viking Age knives of pure iron have been analysed with a view to establishing the provenance of the iron. The ore used for the iron in the knife from Stengade II Grave HÅ was dug up West Jutland; in the knife from Bogøvej Grave S I-II it was dug up on the Scandinavian Peninsula; while the two-edged knife found in Kaagaarden Grave EC was forged from iron extracted from eastern Danish bog ore. Only the iron in the knife from the woman’s grave Ketting Grave XV may have been produced from local bog ore.

A semicircular knife from the Early Iron Age, where the weld was deliberately
 placed along in the centre line of the knife

Knives forged from two pieces of iron with af weld along the centre line

Knives forged from two (or more) pieces of iron that contain less than 0.35% carbon and where the weld was deliberately placed along in the centre line of the knife are defined as Technological Knife Type II. Among the investigated iron knives from the Danish Iron Age and Viking Age, the type is a rare but distinctive element. It has been observed in a semicircular knife from the Early Iron Age and in a narrow, very pointed knife where the tang is almost twice as long as the blade, from the Late Iron Age.

Knives forged from carbon iron

Knives forged from one or more pieces of iron containing more than 0.35% carbon are defined as Technological Knife Type III. Of the 62 knives analysed, two knives were forged with this technique, one of which only has a very slightly elevated carbon content.

Knives forged from two pieces of pure iron and one piece of carbon iron

Knives forged from three (or more) pieces of iron, where the middle piece or pieces were extended right through to the back of the knife and contained more than 0.35% carbon, and where the outermost pieces contained less than 0.35% carbon, are defined as Technological Knife Type IV. Of 40 analysed knives from Late Iron Age graves, 22 were forged as Technological Knife Type IV. NM C 5906 is so far the earliest dated Danish knife that was forged as Technological Knife Type IV. The knife was found in Grave 5 at the burial site Lousgaard on Bornholm and can be dated to shortly before the year 600. The carbon iron that was used for the knife cannot be traced to the Danish area.

 Knife forged from two pieces of pure iron and one piece of carbon iron
Viking Age, Bornholm, Denmark 

Knives forged from two pieces of iron and one short piece of carbon iron

Knives forged from three (or more) pieces of iron, where the middle piece or pieces were not extended all the way through to the back of the knife and contained more than 0.35% carbon, and where the outermost pieces contained less than 0.35% carbon, are defined as Technological Knife Type V. Four Danish iron knives of Technological Knife Type V have been found. They have all been dated to the Viking Age. They are single-edged, straight iron knives from Grave BTY at Kjølvejen/Over Hornbæk, Grave 332 at Nordre Grødbygård, Grave DB at Stengade II and probably from Grave XVI at Ketting.

Knives forged from pure iron with carbon iron in the blade

Knives forged from two (or more) pieces of iron, where the knife-edge was welded on as one or more pieces of iron with over 0.35% carbon, are defined as Technological Knife Type VI. Knife FRM S7x89 from Birkely is the only knife in the study that was forged in this way.