The time-depth of mobility

The study of mobility has been at the heart of research on the Nordic Bronze Age for several decades and with good reason: varied material evidence suggests that long-distance movement was frequent (e.g. Cresswell & Merriman Reference Cresswell and Merriman2011; Holst & Rasmussen Reference Holst, Rasmussen, Bergerbrant and Sabatini2013; Kristiansen et al. Reference Kristiansen2017; Frei et al. Reference Frei2019). Isotopic analyses have provided fresh evidence for the mobility of individuals (Frei et al. Reference Frei2019; Felding et al. Reference Felding, Reiter, Frei and Vandkilde2020; Andreasen & Thomsen Reference Andreasen and Thomsen2021) and warfare and raiding mobilised widely dispersed populations (Price et al. Reference Price2019).

Mobility is also inherent in the cosmology of the Nordic Bronze Age. The acquisition of bronze relied on long-distance networks; it is therefore no surprise to find that aspects of travel are so common in the iconography on bronze razors and in rock art (Kaul Reference Kaul1998; Goldhahn Reference Goldhahn1999; Ling Reference Ling2008). The association of wheels, wagons, ships and sun symbols speaks to the intrinsic entanglement of travel and the movement of the sun (Kaul Reference Kaul1998; Kristiansen Reference Kristiansen, Fredell, Kristiansen and Criado Boado2012). Monumental landscape features also express this cosmology—most obviously in alignments of barrows, some of which stretch for several hundred kilometres (Müller Reference Müller1904; Johansen et al. Reference Johansen, Laursen and Holst2004). Differences in the lengths and orientations of these lines suggest that movement took place on multiple scales, with both economic and cosmological motivations (Løvschal Reference Løvschal, Fontijn, Louwen, van der Vaart and Wentink2013). The construction of these barrows using turves cut from pastureland and the barrows’ sun- or wheel-shaped plans further reinforce these links (Holst et al. Reference Holst, Rasmussen, Kristiansen and Bech2013).

A scholarly focus on heroic, prestige-driven travel suggests that the demand for bronze generated these mobility patterns and their cosmological associations (Ling et al. Reference Ling, Earle and Kristiansen2018), with strategic (marriage) alliances bolstering these networks (Kristiansen & Larsson Reference Kristiansen and Larsson2005; Mittnik et al. Reference Mittnik2019). Following this logic, long-distance movement is argued to be a relatively novel development of the Bronze Age (Frei et al. Reference Frei2019), though some have suggested potential origins in the Late Neolithic (c. 2300–1700 BC) copper trade (Vandkilde Reference Vandkilde1996). However, we question whether the desire for metal alone could have generated such a system, because this kind of mobility relied on a landscape primed for movement in which safe-passage, trust and reciprocity could be expected. In this article, we argue that an emerging entanglement of cosmological and economic landscape practices in the third millennium BC produced an ‘ancestral commons’ through which subsequent Bronze Age terrestrial networks were established and maintained.

Emerging landscapes of the third millennium BC

The geological and topographical form of western Jutland was shaped by glaciation. The area west of the Weichselian boundary is roughly characterised by three main landscape types: low, sandy hills formed from Saalian moraines; mostly flat plains produced by Weichselian outwash; and narrow coastal areas of dunes and marsh (Figure 2). Throughout, the soils are sandy and acidic, better suited for forest or heathland pasture than intensive prehistoric agriculture (Odgaard Reference Odgaard1994). Today, the area has a temperate oceanic climate with an average yearly rainfall of 600–800mm and an annual growing season of 200 days (Cappelen Reference Cappelen2011). There are significant seasonal differences in daylight (17.5 hours/day in summer, 7 hours/day in winter). Temperature fluctuations are, however, moderate due to the North Atlantic Gulf Stream, with mild summers and cool winters, and occasional frost and snow (Cappelen Reference Cappelen2011).

Figure 2. Landscape characterisation of Denmark, showing the Weichselian boundary. Data: Institut for Agroøkologi, Aarhus Universitet (figure by M. Haughton).

While it is widely recognised that the pre-agricultural landscape of northern Europe was dominated by forest, the long-term presence of shade-intolerant species such as oak and hazel suggests that some openings in the canopy must have existed (Vera Reference Vera2000). In Jutland, earlier Neolithic Funnel Beaker Culture (c. 4000–2850 BC) communities grazed cattle in these clearings, a practice that may have increased the size of the openings (Hübner Reference Hübner2005: 702–7). Nevertheless, the Early Neolithic landscape afforded few ‘visionscapes’ (cf. Tilley Reference Tilley, Whittle and Cummings2007). Small clearances for slash-and-burn agriculture are attested during the fourth millennium BC in northern Jutland, changing the character of the forest with secondary birch and hazel growth replacing mature woodland (Kristiansen et al. Reference Kristiansen and Austvoll2021). Pollen findings from Hassing Huse Mose in Thy, also in northern Denmark, reveal local growth of hazel-dominated woodland prior to the SGC expansion—perhaps indicating the practice of coppicing for cattle grazing (Andersen Reference Andersen1995). There followed a dramatic turnover in vegetation, and presumably grazing regimes; over just 30 years, beginning around 2640 BC, hazel pollen dropped from 51 per cent to just 5 per cent of arboreal pollen and grassland pasture expanded (Andersen Reference Andersen1995).

In western Jutland, a similar trajectory gave rise to anthropogenic heathlands. Odgaard et al. (Reference Odgaard, Ejrnæs, Näsman, Rasmussen, Møller, Ejrnæs, Höll, Krogh and Madsen2002) have recorded increased proportions of pollen from herbaceous species on sandy, well-drained soils in western Jutland during the third millennium BC, suggesting these soils particularly afforded heathland openings. In the fourth millennium BC, an increase in disturbance-indicator species such as Plantago lanceolata suggests ongoing small-scale clearances for husbandry and/or agriculture (Odgaard Reference Odgaard1994). Regional pollen trends suggest that the steady expansion of heathland began c. 3000 BC (Figure 3a), though recent work demonstrates that some localised growth could be rapid and radical (Figure 3a; Haak et al. Reference Haak, Kristiansen, Kroonen and Willerslev2023). Pollen preserved beneath barrows suggests that early heather-dominated areas were patchy and that SGC barrows were preferentially associated with these areas (Andersen Reference Andersen1998; Figures 3b & 4). The moraine, for example at Lake Solsø, accommodated larger stretches of heathlands while the sandy soils close to the Weichselian boundary, such as at Skånsø, supported more mixed vegetation (Odgaard Reference Odgaard1994). In contrast, towards the eastern boundary of the meltwater plains (e.g. at Skærskovgård), there would have been little heathland before the Late Bronze Age. Across western Jutland, the Late Neolithic saw a period of relative stagnation in heathland expansion, though notably, heathlands were maintained with regular burning (Odgaard Reference Odgaard1994). Burning is required every 6–15 years to prevent succession to scrub and forest (Gimingham Reference Gimingham1992: 56–7). Clearance resumed in earnest during the Early Bronze Age in both northern (Kristiansen et al. Reference Kristiansen and Austvoll2021: fig. 20.2) and western Jutland (Figure 3). Within these new heathland landscapes, novel funerary structures emerged: low mounds covering single inhumation graves. Initially, the construction of these barrows focused on the sandy, heath-supporting soils (Hübner Reference Hübner2005). The mounds are typically multi-phased, with pioneer graves dug into the ground or beneath low barrows. Subsequent burials might be used to enlarge existing mounds or new barrows might be added to alignments of barrows (Glob Reference Glob1944).

Figure 3. Comparison of regional and local vegetation trends in western Jutland, showing (a) regional and local estimations of land cover composition at three lake sites (redrawn from Odgaard Reference Odgaard1994: figs 48, 71 & 90; Haak et al. Reference Haak, Kristiansen, Kroonen and Willerslev2023) and (b) the local composition of landscape immediately preceding barrow construction during earlier periods of the Neolithic (grey) and the SGC period (black) (adapted from Andersen Reference Andersen1998: fig. 2 and annotated with data from figs 4–7) (figure prepared by M. Haughton).

Figure 4. Possible appearance of third millennium BC heathland in western Jutland, showing a mix of Calluna, herbaceous species and light open forest (New Forest, Hampshire, UK. Credit: soilnet.com).

The origin of these funerary traditions is still debated. The local impact of broader continental-scale migrations is difficult to assess because human remains are rarely preserved in Jutland, particularly in the core SGC expansion area. Archaeological and ancient DNA evidence, however, suggest migration was a factor (Egfjord et al. Reference Egfjord2021), and there were clear links in material culture and burial practices across Corded Ware-using communities in northern Europe (c. 2900–2000 BC). At the same time, local traditions remained important (Furholt Reference Furholt2014) and continuity of site locations and of funerary and depositional practices require explanation (Rostholm Reference Rostholm1982; Klassen Reference Klassen2005; Madsen Reference Madsen2020).

Hence, during the third millennium BC, a new kind of social and economic niche emerged, tied specifically to the sandy, nutrient-poor landscapes of western Jutland. This niche provided new affordances for seasonal grazing, with consequent demands for livestock and human mobility. Rather than merely providing a grazing ‘resource’, these heathlands were produced by social changes that allowed new possibilities to be discovered in the landscape. Moreover, the presence of the ancestors in these new landscapes was significant from the outset and novel burial forms seem to have responded to the growing openness of the landscape.

The emergence of ancestral commons

The co-occurrence of pastoral herding and new forms of burial in the emerging and expanding managed pastures of the third millennium BC suggests an important link between these practices. Rather than seeking an explanation which focuses on the pragmatics of subsistence in SGC communities, we recognise that worldviews emerge from embodied experience and interaction with the world. At every point, the entangled elements of this world emerged and gained significance in relation to one another. Instead of simply seeking pasture and then developing cultural and cosmological practices later, landscape and culture co-emerged; the emergence of heathlands was embedded in particular cultural (barrow-building) and economic (transhumant herding) practices and vice versa. This should not surprise us, for it has long been recognised that the division between ritual and profane is a product of modern worldviews (Brück Reference Brück1999; Bradley Reference Bradley2005). Instead, an entanglement blurred the boundaries between the heathland pasture, pastoral mobility and the ever-visible barrows for the dead. Living and acting in the presence of the ancestral dead fosters and strengthens associated practices (de Coppett Reference de Coppet, Barnes, de Coppet and Parkin1985).

Once emerged and entangled, heathlands created novel niches with new social affordances, which we call ‘ancestral commons’. As pastureland was intermittently visited and managed, heathlands must have been ‘held in common’—jointly owned and/or managed by social groups—and thus would have fostered a sense of community. At the same time, they were landscapes that recreated, confirmed and communicated a sense of common pasts. Via these two kinds of ‘commons’, heathlands became focal sites that orientated people and livestock around a shared cultural background, activated and reinforced by the nexus of practices pertaining to heathland maintenance, barrow-building and movement around the landscape that sustained them. These were all practices that required knowledge—both cosmological and practical. For instance, grazing and controlled burning require particular skills and reveal an orientation towards future outcomes (Noë Reference Noë2006; Dreyfus Reference Dreyfus2014). In this sense, all these practices would have acquired meaning within the spatial and temporal horizons of the heath pastures.

This form of ancestral commons has specific capacities in terms of persistence. Heathlands were caught in rejuvenation cycles (e.g. burning practices, transgression of the life/death of plants), reincarnation (e.g. funerary contexts, movement across threshold of human life/death), and return cycles (e.g. seasonality, the back-and-forth movement of people/animals). These cycles would have been linked to the ancestors through oral narratives as well as made tangible in the physical and visual qualities of funerary monuments. Moreover, the persistence of the heathlands would have constituted a stable landscape to which people could return, one distinct from other landscapes (Løvschal Reference Løvschal2022).

To elaborate these ideas, we trace the emerging relations between these elements beginning with the most archaeologically visible—barrows.

Heathlands and mobility

While heathlands emerged on the sandy soils of western Jutland, grassland and shrub pastureland developed in deforested areas in eastern Jutland (Odgaard & Rasmussen Reference Odgaard and Rasmussen2000). Grass provides preferable grazing during the early part of the year for sheep and, in particular, cattle (Ferreira et al. Reference Ferreira2013). As heather maintains good nutritional value throughout the year, seasonal movement between these pastures and heathlands is likely. It is possible that transhumant herding covered distances of up to 90km (e.g. from Djursland in eastern Jutland to west of the Weichselian boundary), falling well within the range of historically attested pastoralism in northern Europe (Costello & Svensson Reference Costello, Svensson, Costello and Svensson2018). Repeated visits are also suggested by the careful maintenance of heathland. While birch burning at Vroue resulted in deformed pollen (Andersen Reference Andersen1998), heathland fires were actively managed to prevent destruction of the seed bank. Nevertheless, burning an area required pastoralists and herds to move on while the vegetation recovered. Thus, the rhythmic movement of humans and animals was integral to Neolithic heathland living.

The archaeological record also strongly suggests mobility. Examples of the two-aisled longhouse, which became the norm later in the SGC period (c. 2600–2350 BC), are scarce in western Jutland during the third millennium BC. Instead, at that time, the archaeological evidence—typically a few postholes and associated depressions—suggests that settlements were of an ephemeral nature. Similarly, finds are limited to small quantities of pottery sherds and worked flint with a few simple finished tools (Simonsen Reference Simonsen1987). Glob (Reference Glob1944: 245) recognised that SGC barrows frequently contained material derived from domestic activities and reasoned that settlements must have been located nearby. Limited evidence has been found, however, and no settlements are known from areas where the earliest burials occurred (Klassen Reference Klassen2005; Figure 5).

Figure 5. Comparison between SGC settlement sites and the phases of funerary activity (phases after Müller & Vandkilde Reference Müller, Vandkilde, Austvoll, Eriksen, Fredriksen, Melheim, Prøsch-Danielsen and Skogstrand2020: fig. 2.3; settlement data collected by K. Stæhr Gregersen) (figure by M. Haughton).

Some settlement sites may represent permanent or semi-permanent bases in later periods (see also Simonsen Reference Simonsen2017). This typically occurred beyond the core area of the initial SGC expansion, as at Vesterbæk where a series of two-aisled longhouses were situated close to SGC barrows and macrofossils of heather and charcoal were recovered (Møller Reference Møller2011). While the site is not well-dated, it may represent a more permanent base that operated in tandem with the seasonal mobility of some or all of the community into the heathland zone. The settlement at Rævind Hede may represent a similar base, located near SGC barrows at the northern extent of the heath-supporting soils, though its date is also uncertain (Terkildsen Reference Terkildsen2020).

In summary, rhythms of mobility were critical in the emergence and maintenance of heathland pasture. The requirement for repeated visits instantiated a particular relationship between humans and heathlands in which the landscape was repeatedly visited but only permanently inhabited by the ancestral dead.

Barrows and mobility

Linear arrangements of stone-marked graves were present in north-western Jutland as early as the late fourth millennium BC (Johannsen & Laursen Reference Johannsen and Laursen2010). SGC barrows were, subsequently, the first linear arrangements of mounded funerary monuments in Jutland. Müller (Reference Müller1904: fig. 15) recognised a 6km-long line of barrows at Dommerby (Figure 6). Another, more than 5km in length, is known from Trehuse, running along the Weichselian boundary (Hübner Reference Hübner2005). These arrangements created directionality in the landscape, working as ‘way points’ along which people could have moved (Løvschal & Fontijn Reference Løvschal and Fontijn2019). Typically following ridges and naturally dry routes, they seem to direct rather than restrict movement. Thus, barrows began to outline a landscape infrastructure that emerged alongside open landscapes and the mobility of people and herds across Jutland.

Figure 6. Alignment of Neolithic barrows parallel to a historical road at Dommerby Hede, northern Jutland (Müller Reference Müller1904: fig. 15) (figure by S. Müller).

The initial SGC expansion (2850–2650 BC) was marked by a particularly active phase of barrow building. Indeed, the majority (59%) of SGC barrows were constructed during the first two centuries of the period (Hübner Reference Hübner2005). During that time, Hübner (Reference Hübner2005: 468) estimates that five out of every six burials resulted in the construction of a new, low barrow. This large-scale barrow-building activity had important and long-lasting structuring effects on the landscape. By marking areas of newly opened pasture, barrows motivated people's return to these areas—as a result of both cosmological draw and for acts of commemoration and subsequent barrow building. This landscape structure and ways of moving through it were reinforced by each subsequent mound, in the same way as has been argued for the subsequent Early Bronze Age (Johansen et al. Reference Johansen, Laursen and Holst2004). As time went on, burials were more likely to be inserted into existing monuments (only every fourth burial now received a new barrow, Hübner Reference Hübner2005), presumably in connection with now-established seasonal patterns of movement partly marked out by barrow constructions. Thus, barrows instantiated and maintained rhythms of mobility.

The artefacts accompanying the dead also referenced distance and mobility. At Refshøjgård, excavation of an early SGC barrow recovered a beaker whose form blends local traditions and exotic influences; the excavator has suggested that the potter had seen beakers from central Germany (Klassen Reference Klassen2005). Later in the period, ‘A-horizon’ SGC artefacts suggest links with the wider Corded Ware world (Furholt Reference Furholt2014).

Human and animal remains are rarely preserved in the sandy soils of western Jutland and mobility within Jutland cannot currently be detected using standard isotopic techniques due to the low variation in radiogenic signals (Frei et al. Reference Frei, Frei and Jessen2020). Nevertheless, at Møgelvang, in northern Jutland, an individual dated to 2901–2586 BC had a non-local strontium isotopic signature, indicating an origin outside of modern Denmark (van der Sluis et al. Reference Van der Sluis, Daly, Frei and Reimer2020). These remains were derived from a disturbed Early Neolithic tomb, which had been subsequently reused multiple times in antiquity. Additionally, one of seven individuals buried in a SGC cist at Gjerrild, in eastern Jutland, had a non-local isotopic signature (Frei et al. Reference Frei2019). The genomes of three of these individuals also indicate significant Steppe ancestry (Egfjord et al. Reference Egfjord2021), providing further evidence that the SGC phenomenon was associated with long-distance mobility, at least at its outset. None of these examples, however, comes from a typical SGC barrow.

Hence, barrows emphasised connectivity and movement. They monumentalised mobility, for example, through the deposition of objects that reflected the connections formed by that movement and—through the use of heathland turves in their construction—links with the very land that motivated and enabled mobility.