From commodity to singularity: The production of crossbow brooches and the rise of the Late Roman military elite

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Highlights

  • Sociocultural change studied through the life history of an entire artefact type.

  • XRF and metric data enhanced the traditional crossbow brooch production model.

  • Dimensional variation was successfully used as a typological tool.

  • Variations in composition and dimensions were linked to regionality and state-control.

  • Changes in Roman military and elite society were studied through product organisation.

Abstract

The diachronic development of the crossbow brooch was examined for northern Gaul during the Late Roman period (3rd to 5th century) in order to extrapolate changes in production organisation from variation in the copper-alloy composition and shape of the artefacts. A combined method of surface analysis by handheld XRF and dimensional analyses by focussing on variation or similarity was applied and interpreted in a typological framework to confirm and enhance the traditional production model of the crossbow brooch. This led to new insights into the processes of regionality and state-control in Roman metal production in a provincial context. From a simple military commodity to an elite symbol of power and authority, these changes in production and consumption reflect sociocultural changes in the Late Roman West.

Introduction

The relationship between the production of objects and social organisation is vital for archaeologists working to understand the link between artefacts and past societies (e.g. Costin, 2001, Peacock, 1982, Underhill, 2003). Traditionally, the distribution of stylistic features of objects such as lithic tools, ceramic pots or metal dress accessories are used to investigate production organisation. Recently, more studies focus on compositional analysis to explore production processes. Too often, these two approaches are used separately, whereas the chaîne opératoire paradigm demonstrates that both aspects are expressions of social practice (Sellet, 1993, Tite, 1999). A third aspect, represented by the object biography and life history concepts (Dannehl, 2009, Kopytoff, 1986), stresses the importance of incorporating the sociocultural context in order to understand the changes in both artefact and society. Despite the success of these approaches, the production and compositional variation related to social change remains understudied for many Roman brooches, such as the crossbow brooch.

This specific brooch type is closely associated with the Late Roman world (3rd – 5th century) and is well documented in archaeological and art-historical studies. Despite its rich research history, not much progress has been made recently in understanding the link between changes in the production organisation and the transformations of the Late Roman society. Hypotheses on state control and regionality have been formed based on the style-distribution patterns (Swift, 2000), but still remain unchallenged by other methods. This study explores the changes in the crossbow brooches' physical properties – composition and dimensionality – over time and changing social context to gain new insights in the production organisation and its reflection of the growing influence of Late Roman military elite.

The crossbow brooch is a Roman bow brooch. Its main functional attributes are the bow and arms (or crossbar) containing the hinge mechanism and pin attachment, which is set in the foot. Its most distinctive features are the knobs (or terminals) at the end of the arms and at the front of the bow (Fig. 1, Fig. 7). Production techniques include casting in moulds, the working of solid metals, or assembling various parts made by either casting or working. They are often decorated by motifs and patterns along the foot and bow and contain decorative features on the arms and base of the bow. These decorations were either present in the mould or made by cutting, stamping and soldering. Some brooches can also exhibit gilding, silvering and niello as added decorative features (Bayley and Butcher, 2004, Dandridge, 2000, Swift, 2000).

Interest in the crossbow brooch started in the first half of the 20th century and a wide variety of scholars created many different typologies (for an overview see Swift, 2000, Van Thienen, 2016). The typology applied here is based on the model of Keller (1971), consisting of six successive types, with the adjustments made by Pröttel (1988) and Swift (2000) (Table 1). In order to incorporate the direct predecessor of the crossbow brooch, this study introduces a ‘type 0’ into this ‘Keller-Pröttel-Swift model’ (Fig. 1.1). Although, despite the longstanding research history, some issues concerning chronology and provenance have to be noted. The dating of the (sub)types is limited by the uncertain lifespan of an individual brooch between production and deposition or recycling. Also, a large number are stray finds or have poor contextual information. Additionally, there is a depositional bias towards burials favouring crossbow brooches from the mid-4th century onward. These burial gifts were taken out of circulation, and the recycling flow, and are more likely found by archaeologists than their predecessors.

Initially, these brooches were considered to be military artefacts exported from a central state-run workshop (fabrica) in Pannonia or Illyricum (Riha, 1979). Although the general shape is very similar throughout the different types, there are distinct stylistic differences per region, postulating that a series of smaller workshops could have been active in different locations. The interregional comparison made by Swift (2000) demonstrated that the crossbow brooches' evolution is shaped by regional dynamics, chronological overlap and changing production processes. Swift created a narrative of a continuing mainstream trend that achieved a wide distribution alongside parallel smaller divergent groups with regional characters and restricted spread. Workshops locations in northwest Gaul and the Danubian provinces were proposed for the early 4th century (type 1 and 2), with limited distribution clustering along the frontier zone. For the largest part of the 4th century, the Pannonian production (type 3/4) is considered to have exported crossbow brooches across the entire Roman Empire, alongside localised pockets of production, until this central workshop ceased producing at the end of the 4th century. At this point, small workshops in the area west of the Rhine are suggested to have continued production into the 5th century (type 5 and 6), characterised by a distribution away from the frontiers and changes in symbolism resulting in a higher status. Evidence of small scale localised production was found in a workshop in northern Italy (Giumlia-Mair et al., 2007), but more confirmation for Swift's style-distribution model was acquired by the compositional study of British brooches (Section 3.1).

Section snippets

Materials and methods

The physical properties of Roman brooches are mainly investigated by compositional analyses (e.g. Bayley and Butcher, 2004, Bayley, 1998, Dungworth, 1997, Giumlia-Mair, 2005, Riederer, 1993), although often brooches cannot be damaged for analyses because they are part of invaluable collections. Portable X-ray fluorescence (XRF) provides a mobile, quick and inexpensive solution to analyse large collections non-destructively, which motivated the choice for using a portable device here. However,

Composition and typology

In the 557 measurements performed on a total of 187 brooches from the Low Countries, 14 elements were detected: Si, K, Ca, Fe, Ni, Cu, Zn, As, Ag, Sn, Sb, Au, Hg and Pb. Their varying presence and intensities are related to the major and minor elements of the copper ore (Cu, Ni, As, Sb, Ag), alloying metals (Zn, Sn, Pb), decorative precious metals (Ag, Au, Hg), corrosion and soil contaminants (Si, K, Ca, Fe), and the hXRF device (characterisation of the hXRF instrument showed a contamination of

Discussion

An important final step is to link these interpretations on production to the attested changes in the sociocultural contexts in the crossbow brooch's life history (Swift, 2000, Van Thienen, 2016). During the second half of the 3rd century, this artefact arose as a new type of bow brooch originating as a soldier's uniform attribute in the Danubian area. Not much is known about this first phase (type 0 to 1), other than that archaeological evidence places it predominantly on military frontier

Conclusion

To conclude, we can state that despite certain limitations in non-destructive surface analyses, good results and new insights can be obtained to investigate the relation between composition and production for an extended time period in a complex setting. Additionally, the use of metric variation through shape and dimensional change to explore differences in production organisation displayed much promise. Moreover, by investigating the complete (regional) life history of a symbolic artefact such

Acknowledgements

This study is part of the research project “Decline and fall? Social and cultural dynamics in the Low Countries in the Late Roman Empire (AD 270-450)”, supported by the Netherlands Organisation for Scientific Research (NWO) and the Research Foundation – Flanders (FWO) (GA04612N). We wish to thank the following museums and institutions for allowing us to perform analyses on their collections: Agentschap Onroerend Erfgoed, Romeins Archeologisch Museum Oudenburg, Gallo-Romeins Museum Tongeren,

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