*Study Site*

The Bronze Age burial mound of Seddin (colloquial: 'King's Grave', German: Königsgrab Seddin), which was discovered in 1899, is widely known for its tremendous size and the valuable funerary goods made from bronze, iron, glass, and stone (e.g., [29–31]). It was dated to approximately 800 BC (period V of the Nordic Bronze Age) and has a central role in the regional cultural landscape, which today covers the north-west of the federal state of Brandenburg and southern Mecklenburg [32,33]. While past studies found the surroundings of the burial mound to be heavily shaped by human influence, which occurred during the Bronze Age [31,34], the 'King's Grave' keeps an outstanding position, both regarding its geographical location and its rich physical characteristics. Estimates by May [35] see the total height of the mound between eight and ten metres. The burial mound is separated spatially from smaller groups of burial mounds in the surrounding area. It is located on a slight spur, surrounded by multiple waterbodies [31]: 900 m east of the burial mound runs the river Stepenitz, and in the north and south, two of the river's tributaries delimit the burial mound from its surroundings (Figure 1). The parent material is dominated by Pleistocene deposits, composed mostly of fine to coarse glaciofluvial sand with little or no gravel [36]. West and south of the burial mound, clayey to sandy silt can be found. In the hollows, associated with the two tributaries of the Stepenitz (Figure 1), muck soil of a sand–humus mixture dominates, which overlies fluvial and periglacial deposits [36]. The relief of the surrounding landscape is characterised by a smooth, rather levelled topography that is dissected by depressions and river valleys. Regarding the wider vicinity, several burial mounds of similar size are known but have mostly been destroyed and lack any archaeological record [31,37]. Regardless of the nature of these undocumented burial mounds, their sheer amount reflects the importance of this landscape during the late Bronze Age. Brunke et al. [38] see the 'King's Grave' of Seddin as the clearest manifestation of an accumulation of wealth and power in this area around the middle reaches of the Stepenitz.

**Figure 1.** Location of the study site: (**a**) Surroundings of the burial mound; (**b**) location of section SD17P1. Elevation data: LiDAR-based DEM (1 × 1 m) by Geobasis-DE/LGB 2013 (R. Hesse; modified).

Within this study, we examine section SD17P1 (297601 E, 5891584 N; WGS84; UTM 33N), which was documented in 2017 during an excavation on the north-western slope of the Bronze

Age burial mound of Seddin. The investigated section faces north, is approximately 3.2 m high, and consists mainly of anthropogenic layers: Only the lowermost 20–40 cm are interpreted as the buried local soil (Figure 2c,E), which was dated by three14C-AMS ages to the ninth century BC [33]. The remaining part of the profile consists of discrete layers, which were piled up during the construction of the burial mound with alternating layers of stone and sand that were deposited on top of each other. In addition, there is a horizontally running, thin, dark layer, which crosses the lowest artificial sand layer (Figure 2c,C). The type of construction with stone layers at hand is congruent with the findings of Brunke et al. [38], who examined the south-eastern side of the burial mound in 2013. However, the diagonal segmentation and orientation of sand layers B and D is only present in SD17P1. The topmost stone layer of SD17P1 most likely represents the Bronze Age surface, which would, in addition to the prominent position of the mound, emphasise its monumental character (cf. [33]).

All analyses carried out in this study focus on the parts of the profile that lie above the lowest layer of stones, which is approximately 200 cm below the surface of the burial mound. Layer E (local soil) is therefore excluded from the processing (Figure 2c).

**Figure 2.** Archaeological section examined. (**a**) Location of the sediment samples taken; (**b**) overview of the section; (**c**) drawing of the archaeological section examined. Layers A to D are part of the anthropogenically created burial mound. Layers B and D consist of numerous diagonal layers, which are summarised here. Colour and texture of the sediments were documented during fieldwork and are presented in Figure 5 along with the sedimentological record (Section 3.1). Layer E is interpreted as the local soil that was buried during the construction of the burial mound [33] and is excluded from all analyses.
