Extensibility of Callmer's Bead Typology

Author: Neil Peterson
This article was written for a second year archaeology course and provided a reason to examine a number of other finds of viking era beads. It is extremely simplistic but provides a background on typologies, especially Callmer's bead typology, and a listing of many beads outside the original scope of Callmer's paper.

In studying the Viking era Scandinavian cultures the importance of beads cannot be overstated. Historical sources are rare in the study of the Viking world but beads are so important that their value is noted by Ibn Fadlan in his Risala of 921 A.D. He notes that green glass beads are highly prized and that high prices can be paid for them.

Only one authoritative study of the corpus of beads exists and it has several significant weaknesses. In spite of the concerns Johann Callmer's typology must form the basis for any cross site comparison of Viking era beads. This paper examines how well beads previously excluded fit within the typology and how it can be extended to include materials that do not directly fit.

Background

In 1977 Johann Callmer published his dissertation entitled Trade Beads and Bead Trade in Scandinavia ca. 800-1000 AD. This book documents 14995 beads from 299 graves. The first of the problems with this thesis occurs at this starting point. Callmer deliberately excludes many different types of beads and any site with less than 10 beads. This was done to ensure that the relationships between the types of beads within a find are statistically significant and thus relevant to the chronology that Callmer was focused on creating. This will have the unintended consequence of perhaps excluding rare beads.

A second issue arises with the beads excluded due to their construction material. As Callmer's work considers beads from cremations as well as inhumations he excludes amber, metal, and jet beads as none of them is likely to survive a cremation. These are excluded so that the type of burial which may be chronologically or geographically influenced does not impact the statistical correlations.

The beads within the thesis are examined from a number of directions including the construction material, construction techniques, colour, transparency, decoration, size, shape, and proportion. Although ten techniques of construction are identified only two (folding and drawn tubes) are directly used in the determination of type. Twenty-seven shapes are identified which is a significantly larger number than are used in other papers. Nine shapes are deemed sufficient by Lundström in her paper on the glass from Helgö, and Ambrosiani's work on Birka.

Size and proportion are treated using two parameters. Size is measured in millimeters across the axis of the mandrel hole. Available diameters are grouped into eleven values each of which is 3mm in range such as value 162 which includes beads with a diameter of 3 to 5 mm. Proportion is given one of four values based on the length to diameter ratio.

Callmer then divides the beads into twenty-four colour groupings using a purely subjective colour scheme rather than using Munsell colours as in Lundström, or measuring the reflection values as a range of wavelengths. Similarly the translucency of the beads is visually “established quite subjectively in strong light” (Callmer 1977: 35) Decoration is the final attribute. Callmer identifies 109 different groupings of lines, dots and eyes, and patterns of these elements. Again it is worth noting that the typology is incomplete in that no effort is spent to detail, or include within the typology the colours of the decorative elements.

Using combinations of these attributes the beads were grouped into 595 types. It is interesting to note that some of these types, for example A014, have no representative beads. No explanation is given for the creation of the type without a bead to match. The types themselves need to be discussed further as they are another possible source of issues. Some types are highly specific limiting beads to a single shape, single proportion, colour, transparency, and single 3 millimeter range of diameters. One example of this would be A043, monochromatic translucent yellow glass beads rounded with plane parallel ends between 12 and 14 mm in diameter with a length/diameter ratio less than or equal to ½. Other types show a much higher variability with shapes, proportion, size, colour, and translucency often accepting a range of values rather than being restricted to a single value. An example of this would be type A024 monochromatic cylindrical opaque glass beads either white or grayish white ranging in size from 3 to 8 mm and with a length/diameter ratio greater than or equal to 1 (proportion values 153, 154).

The types are then examined chronologically within 12 main and 6 intermediate periods. This preliminary analysis brought to light some concerns with the initial assumptions. Almost 15% of the sites could only be placed as addenda within the periods. For this reason the chronological periods were reconsidered and consolidated into nine periods reducing the required exceptions.

Fifty-three groups combining various types are created and the groups discussed in their chronological placement. The bead groups are then further examined in an attempt to locate the provenience of the various groups. This geographical placement is done on the basis of visual similarities, and where possible material availability such as with rock crystal. It is interesting that Callmer notes “In conclusion we may suggest that there may have existed occasional bead production at several places but that the existence of these is doubtful and, if they existed, their importance for the total supply of beads was insignificant.” (Callmer 1977: 102) Yet Lundström's paper documenting such production at Helgö was published a year earlier and is mentioned in a footnote within Callmer's paper. Five years of excavations at Ribe had also just been completed providing compelling evidence of a long running seasonal glass bead production workshop, although this information would take years to be published.

Extending Callmer's typology

The corpus of Viking era Scandinavian bead materials is far larger than was contained in Callmer's work. This paper will explore beads from finds smaller than those accepted by Callmer as well as finds that were not available to Callmer in an attempt to prove that the typology can encompass beads excluded from the original thesis, or expanded within a compatible framework to include beads that do not fit into existing classes.

An extended typology would provide a boarder base of comparison of beads within the Viking world as well as enhancing the ability to spot outliers in archaeological sites.

To test the robustness of the proposed typology it is necessary to explore how a number of finds would map into the provided types. A major difficulty with this process will be that articles covering a number of beads often fail to provide detail on each bead at a level required to place it within the typology. For this reason the material from each paper will be examined in the depth allowed by the details contained within the paper.

Birka

The material from the Birka finds includes forty-two beads of rock crystal (Callmer type S), twenty-three carnelian beads (Callmer type T), 860 glass beads, twenty-six amber beads, and eight beads with no material provided.

Ambrosiani identifies eight main shapes. From the diagrams provided in the article seven can be directly mapped to equivalent shapes in Callmer's typology. These include spherical (Callmer shape 121), ring-shaped (122), cylindrical (127), faceted (135), barrel-shaped (125), biconical (132), and melon shaped (125). Ambrosiani's eighth type is segmented which is more difficult to map directly to a Callmer type. Callmer treats beads of this type according to their style of production. These are usually produced using a blown glass technique. Callmer classifies these as type 114 or 115 depending on the wall thickness and notes that they are segmented with thongs. Although this technique will work it is also possible to roll glass wound on a mandrel on a textured surface and produce similar results. The lack of information about the wall thickness means that segmented beads cannot be treated as mapped to a specific Callmer type. The final shape that Ambrosiani notes is ‘other' which unfortunately cannot be examined to see if it would fit with the typology.

The Birka material is also divided into eleven colours plus 51 beads marked as being of another colour. The easily mapped colours include: colourless (Callmer colour 201), orange (208), red (209), black (205), violet (213), white (202), yellow (206). Ambrosiani further identifies blue and green beads which cannot be directly mapped as Callmer provides three shades of blue and three of green. Foliated beads both silver and gold are further identified which can be mapped to colours 223 and 224 respectively. It should be noted that although both Callmer and Ambrosiani identify gold foliated beads there is no indication in either case that gold foil was used. So called gold foil beads are actually produced using silver foil and coloured glass (Welander et al 1987: 164)

Thirty-eight of the rock crystal and carnelian beads are noted as being facetted. Based on the drawings provided in the article this shape maps well to shape 135. Callmer identifies class S009 for rock crystal and T009 for carnelian which match both the material and shape of these beads. A further twenty-three beads are identified as spherical (Callmer shape 121). Callmer types S001 and S002 identify spherical rock crystal beads, and type T001 identifies spherical carnelian beads. Without indications of the length and diameter it is not possible to definitively assign these beads to those specific classes but they are acceptable candidate classes. No shapes are given for the four remaining beads of these materials.

The amber beads require an expected extension to the typology. As Callmer uses a letter to identify the material of construction W is proposed as designation for amber beads. Of the twenty-six amber beads thirteen are identified as barrel shaped (Callmer type 122), four as biconical (Callmer type 132), three as facetted (Callmer type 135), and six are not identified by shape. Without indications of the length and diameter it is not possible to create specific classes for these beads. None of the shapes identified, however, are outside the range provided in Callmer's typology.

Ambrosiani identifies 108 monochromatic glass beads. None are provided with a length and diameter so mapping them precisely to Callmer types is not possible. As noted above all of the identified colours and shapes have analogues within Callmer's typology. 100 of the 108 beads have both colour and shape identified, 67 of those can be tentatively mapped to one or more types. The 33 remaining beads fall into two groups. The first consists of a single white biconical bead, and the second 32 white spherical beads. Spherical glass beads are not noted in any class however there is no simple way to distinguish between a rounded bead without plane parallel ends and a proportion near 1/1 and a spherical bead. It is thus possible that the 32 white spherical beads fall within type A025. Without the transparency, length and diameter Callmer's typology cannot be extended with a new class to include the biconical bead but the framework is compatible with this bead.

The thirty-five multicoloured glass beads identified at Birka present more of a challenge in classification. Thirteen of the beads must be immediately excluded from consideration as they do not identify both colour and shape. Of the remaining twenty-two beads half can be reasonably matched to tentative classes. Eight of the remaining eleven are listed as spherical and can fit within established types if the shape and proportion are changed to define the bead as rounded without plane parallel ends and a proportion of 1/1. The remaining three beads are white spherical or barrel shaped and have no analogue within the typology. Again if transparency, length, and diameter were provided it would be reasonable to extend the typology to include them.

Although Ambrosiani identifies 959 beads in the article none are provided with enough information to positively match them to a specific type. At the same time no information is presented about any bead that is incompatible with Callmer's framework. The areas of concern would be the 2% of beads listed with a shape of ‘other', 5.4% of beads with a colour of 'other', and 86% of beads for which a shape and colour are not listed any which may or may not be inconsistent with Callmer's framework.

Dublin

In 1985 Briggs revisited an 1847 find of a burial in Dublin with 9 beads. Although none of the nine beads are given all of the information ideally needed to properly classify the beads, more information is provided than in the Birka material as treated by Ambrosiani. Two of the beads were of amber with a barrel shape (122). This matches the barrel shaped beads found at Birka. From the drawings provided it is possible to also define the proportion of beads as less than ½ (Callmer proportion 151).

The remaining seven beads are glass. Briggs identifies beads a and b as belonging to Callmer's group Bj, and bead c as belonging to group Bf (Briggs 1985: 101). Beads e and f are defined as “globular, featureless, and respectively translucent pale blue and opaque green” (Briggs 1985:101). This suggests a shape of 122 (rounded without plane parallel ends), grouping of A (monochrome glass), proportion of 152 or 153 (length to diameter between ½ and 1.5). Colour and transparency for bead e would be 181 or 182 (translucent or semi-translucent) and 215 or 216 (forget me not blue or grayish blue). This would suggest a tentative match for bead e of A240, A264, or A271 depending on the exact size and colour. Bead f would be 183 (opaque) and a colour of 219, 220, 221, or 222 (depending on the shade of green). This has no candidate matches but is still within the framework Callmer has defined.

Bead g is constructed of twisted glass rods called reticella. Callmer classifies all beads of this construction as type K001. This leaves only bead d which is visually similar to B683, B686, and B724 but cannot be accurately assigned without additional information.

Thus six of the nine beads from this find match candidate classes while the remaining three would require new classes that are compatible with Callmer's framework.

Islay

Gordon's 1990 treatment of a Viking era grave on Islay documents six beads including three of jet, one of amber, two of glass. This treatment provides significantly more detail than the previous articles allowing for a finer level of classification.

Bead a is amber and is an extremely unusual shape with an offset hole. No analogue for this shape exists in any bead of any type in any publication discussed here. If this shape is a result of breakage at or after burial then the remainder does not provide enough material to match the bead to any shape. If not the result of breakage than this bead would require a new shape to be defined. New shapes are, like additional materials, a reasonable extension to the framework Callmer defined but a shape this different warrants significant additional attention.

Beads b and c are presented with enough information to classify them as Callmer types A172 and A040 respectively. It is difficult to determine if the “faint striations” (Gordon 1990: 158) mentioned are scratches, production marks from the motion of the hot glass, or traces of a decoration which would require moving the bead into group B.

The three jet beads like the amber require the definition of a new major type, X is proposed for these beads. The details provided allow the creation of three new classes

	Shape	Diameter	Proportion	Bead
X001	122 (rounded without plane parallel ends)	169 (26 mm)	151 (L/D <= ½)	d
X002	124 (rounded with plane parallel ends)	168 (22 mm)	151 (L/D <= ½)	e
X003	122 (rounded without plane parallel ends)	164 (10 mm)	152 (½ > L/D <= 1)	f

Kneep

The 1987 article on this burial at Kneep on the Isle of Lewis documents forty-four beads all of which are segmented or single segments of a multi-segment bead. Five beads of opaque yellow (183, 206) each of three segments could be members of Callmer Types E030 or E031. The twenty-one clear blue (181, 214) beads of two or three sections are likely types E060 or E061. The final seventeen beads are listed as gold or silver foil with one or two segments likely fitting them to E110, E112 or E130. The documented size of 4 to 6 mm (Welander et al 1987: 155) matches to a size value of 162 or 163 which is compatible with the types mentioned above. Length measurements taken of the scaled drawings (Welander et al 1987: 156) and the overall lengths of 9 to 13 millimeters provided (Welander et al 1987: 155) produce length to diameter ratios from just under 1 to over 1.5 (values 152, 153, 154) which are also compatible with the types provided above. Unfortunately the article does not provide wall thickness which prevents confirming the beads as belonging to these types which are defined as having a wall thickness greater than 0.5mm. Even if the wall thickness of these beads is smaller than 0.5mm, however, the blue beads would match type D001, and the remainder could be easily accommodated in the D beads by adding six new types to match the equivalent E types listed above.

Helgö

Lundström's article on the bead material of Helgö identifies 243 beads and provides additional information about some other bead types. Beads of bronze, amber, silver, rock crystal, amethyst, cornelian (sic), clay, and limestone are identified in addition to the glass beads. Rock crystal (S), carnelian (T), and amethyst (U) are in Callmer's predefined types. Amber (W) was added earlier but new types are required for bronze (Y), silver (Z), clay (P), and limestone (L).

In addition to the commonly used classes: barrel-shaped (124), biconical (132), ring-shaped (122), spherical (121), cylindrical (127), conical (131), cubical (134), polyhedral (135), melon-shaped (125), and segmented (types D and E), Lundström mentions beads made of wound threads which Callmer would call reticella and group in type K001. Colours identified in these beads include red (209), orange (208), yellow (206), green (219, 220, 221), white (202), green-blue (217), blue (214, 215, 216), colourless (201), and black (205). An additional colour of yellow-green is given which may be related to Callmer's grayish green (222) or may require a new colour value (225). The remaining shapes and colours are compatible with the Callmer typology and the additional bead materials and possible new colour are acceptable extensions to the typology.

The “drop shaped” (Lundström 1981: 33) amethyst bead fits within Callmer's type U001 which does not have any sub types, or restrictions on shape or size.

Lundström lists three translucencies: translucent (181), opaque matte and opaque glossy. If both opaque types are mapped to Callmer's opaque value (183) it is possible that some semi-translucent beads are misclassified as opaque but this appears to be the closest match to the author's intentions.

Of the 237 beads found within building group 3, 174 are provided with enough detail to generate a type. Thirty-eight of the beads are polychrome and need to be mapped to Callmer's B type beads, but without additional colour information for the decorations there is not enough information to complete a mapping. It is only possible to note that no decorative style is presented that does not have an analogue already existing within Callmer's typology.

Thirty-one of the remaining monochrome beads, just less than 23%, can be immediately mapped to specific A-types. The remaining 105 beads would require new classes to be created but contain no value outside of the typology.

Extending the research

Several avenues of additional research present themselves in a review of this material in addition to the value of adding additional types and beads into the record. Focusing materials analysis on beads of a single type noted as being prevent in a particular time period would allow a further range of studies. For example trace materials could be used to investigate the number of possible source locations. Combining the results of that and location of deposition could add information about trade networks.

Conclusion

Although the typology proposed by Callmer is incomplete additions to the list of types and materials are easy to accomplish within the outline of the existing framework. The greatest difficulty in accomplishing these activities is in determining all of the information required to accurately assess a bead as belonging to a type or to completely define a new type.

Ambrosiani, Bjorn: 1995 Beads of Glass and Semi-precious Stone. in Birka Studies Volume 2 Excavations in the Black Earth, (ed) Ambrosianai, Björn and Helen Clarke Stockholm 1995 pp. 52-63.
Briggs, C.S.: 1985 A Neglected Viking Burial with Beads from Kilmainham, Dublin, Discovered in 1847. Medieval Archaeology 29:94-108
Gordon, Kate: 1990 A Norse Viking-age grave from Cruach Mhor, Islay. Proceedings of the Society of Antiquaries of Scotland 120: 151-160.
Lundström, Agneta: 1981 Survey of the glass from Helgö in Excavations at Helgö VII: Glass, Iron, Clay. A. Lundström and H. Clarke, eds. Stockholm.
Smith, John Alexander: 1874 Note of Coarse Green Glass Beads found at Kinloch-Rannoch, Perthshire., Proceedings of the Society of Antiquaries of Scotland 10:447-8
Welander, RDE, Colleen Batey, and T.G. Cowie: 1987 A Viking Burial from Kneep, Uig, Isle of Lewis. Proceedings of the Society of Antiquaries of Scotland 117: 149-174.