Participants: Arjen Heijnis, Maria Mertiri (Aarhus University), Silke Eisenschmidt (Museum Sønderjylland).

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1 Excavation report (sb. 104 Broager sogn) Author: Arjen Location: WGS Landowner: Andelsselskabet Smøl vold (chairman Jørn Christensen) Date: Participants: Arjen, Maria Mertiri (Aarhus University), Silke Eisenschmidt (Museum Sønderjylland). Contents: Report, 3 pages Structure list Structure descriptions Finds list Drawing list Picture list Radiocarbon report 12 photographs 2 drawings Introduction Smølvold (also known as Svenskeskansen) is an earthwork close to Flensburg Fjord just north of the village of Broager. The current form of the feature is a near-circular earthen wall up to 2-3 meters high with an indentation in the west side. The site is currently used as a gathering location for the local Danish-speaking majority in the South Danish frontier region, which includes a permanent flagpole and a yearly bonfire in the centre. In 2015 the site was subject to a small trial excavation by the present author from Aarhus University as part of a larger sampling program of the unknown minor Danish ring-fortresses. This was part of PhD project. The aim of the trial excavation was to retrieve a sample for radiometric dating, preferably from the old buried soil horizon beneath the earthwork. This would give a date for the first construction of the earthwork, rather than typological dates from artefacts from the vicinity or dated material from the fill of the ditch, which might date a later re-use phase.

2 Previous fieldwork The site has been subject to a trial excavation in 1932 by the National Museum. The aim of this previous excavation was to retrieve artefacts from a culture layer to date the use of the earthwork. None were found, but previous artefacts from the vicinity include a Late Viking Age sword handle from the ditch fill, a Bronze Age cremation urn, and several pieces of ceramics from the Early Iron Age. The site is protected as an archaeological monument, and no documented archaeological fieldwork has been conducted since Method On the inside of the southern bank of the earthwork, a small one-square meter trial trench was dug to beneath the natural soil at 2 meters depth. From the lowermost soil horizon, samples were taken for C14- dating. Samples were collected in metal Kubiena-boxes and analysed in the AMS 14 C-laboratory at Aarhus University. Measuring system By GPS the four corner points of the trench were measured in, with the following coordinates (WGS84 U32): Easting Northing Elevation

3 Figure 1: the location of the trench Results The sections through the earthwork revealed a complex sequence of more or less clayey layers. Layers 1 and 3 can be understood as a mixed loose fill, whereas layers 5, 6, and 7 are more homogeneous. These different fills most likely correspond to different locations where the material for the fill was taken from. Very clayey yellow layers (5 and 7) correspond to a deep subsoil source, whereas a very humic layer (6) must have been taken from the top of an old soil surface. The transition between the wall fill and the natural surface is very diffuse. This suggests the original surface was disturbed or truncated immediately before construction, so no old vegetation horizon could be identified. It is possible that layer 9 is actually a short-lived pit or trench dug into layer 4, and subsequently backfilled with the same material. The charcoal at the transition between layers 9 and 4 has been radiocarbon dated. This yielded a date of calad (95,4% probability) (fig. 2).

4 Figure 2: The result of the radiocarbon measurement of X1 (A10). Conclusions The 1932 excavation most likely interpreted layer 6 as the natural soil horizon. My excavation however has shown that layer 6 is just another artificial earthwork fill, as it overlays fill layers 7 and 3. The true natural subsoil starts at layer 4. This means that the entire plateau was raised artificially, with the banks subsequently being built up from material from the 6-meter wide ditches. On the basis of this small trial excavation it is impossible to tell whether the two fill horizons correspond to two distinct phases of use of the site, or whether they are distinct architectural elements from a single building episode. The earliest construction, dated by the charcoal found on top of the old soil surface, should be dated to the early medieval period. This corresponds well with the typological date of the swordhandle, which was found in the ditch fill. This find dates the latest use of the feature, being covered by the filling up of the ditch, which suggests a rather short occupation history of the site. This corresponds with the general lack of artefacts, stone architecture, or a culture horizon at the site. It is recommended to extend the trial excavation to the entire width of the wall, so that further architectural elements can be found. The charred wood at the bottom of the wall fill might represent a preserved construction element, which could be traced elsewhere in the structure as well. Furthermore,

5 the tracing of layers 6 and 7 and their relation with the current internal surface of the earthwork might clarify whether the entire hilltop was elevated, or only the core of the bank. Currently, the culture-historical context of the earthwork best fits with the turbulent history of Denmark after the establishment of Christianity in the 10 th century and before the establishment of strong kingship in the 13 th century. Particularly the east coast of Denmark was in this time troubled by piracy from the southern baltic coast, and it is possible that the earthwork was constructed to either defend against piracy, or used as a base by pirates itself. An alternative possibility is that this fort was built by local aristocracy in an attempt to achieve territorial control, like a number of other continental medieval castles. If this were the case, the fort should be situated in relation with other ring-fortresses, predating the motte-type castles that are traditionally seen as the beginning of castle-building in Denmark.

6 Structure list Feature Class Subclass Date Fase Drawing Part of Consists of A1 Fortification Earthwork 1,2 A2 Fortification Earthwork 1 A3 Fortification Earthwork 1,2 A4 Fortification Earthwork 1,2 A5 Fortification Earthwork 1,2 A6 Fortification Earthwork 1,2 A7 Fortification Earthwork 1,2 A8 1,2 A9 Fortification Earthwork 2 A10 Fortification Earthwork See X1 2

7 Structure description A1 Top of earthwork fill. Consists of clayey silt with small and medium stones. Smudgey yellow with a grey A- horizon on the top. With grey and white patches (reduced clay). A2 As A1, animal burrow, grey. A3 Heterogeneous material consisting of clay with gravel, with clay lenses/smudges. Earthwork fill. A4 As A3, but finer texture, less big stones, and no clay. Original soil surface (thick A-horizon). A5 As A1, but with more visible structure. Yellow clay. A6 Black-grey humic horizon, sandy silt, clay percentage <5%. A7 Yellow, compact clay. A8 Undisturbed natural subsoil, yellow sand, medium fine, no gravel. A9

8 As A4, but more gravel and sand, heterogeneous. Diffuse transition to A4, possibly truncation in old soil surface. A10 Charcoal layer, sampled in X1.

9 Finds list X1 Charcoal sample from A10 X2 Kubiena box 1 X3 Kubiena box 2

10 Drawings list Drawing 1: East Section Drawing 2: South Section

11 Photo list FE-nr Photo -nr Description Excavating at the top of the bank Excavation in progress The charred wood in situ (A10) W Arjen W Arjen Depth of A10 W Arjen Packing X1 W Arjen Section W Arjen overview Top south N Arjen section, detail Middle south N Arjen section, detail Bottom south N Arjen section, detail Bottom east W Arjen section, detail Middle east W Arjen section, detail The site E Arjen immediately after restoration Taken from Date Year Photographer S Arjen Acronym J-nr Place Parish Sb-nr

12 AMS 14C Dating Centre Institut for Fysik og Astronomi, Aarhus Universitet Report1687_ xls AAR Name Material (species) Description Submitter C14 age pmc d13c AMS Calibration and correction smølvold 1 Charcoal (ubestemt). The sample would provide a TPQ date for the construction of the above-situated earthwork; whether the sample was part of an in-situ treeroot or is made up of worked wood (a support beam), the sample should narrowly pre-date the construction of the earthwork. The overlaying layer might be either an Iron Age/Early Medieval ringfortress, a Prussian watchpost, or a Bronze Age barrow. Depth: 2 ± m (bl s) Latitude: ,06 ± (WGS84) Longitude: ,55 ± (WGS84) Expected age: C14 age (BP): ; Calendar age: 2000 BC AD Arjen 891 ± ± ± 1 Calibration curve: IntCal13 (Atmospheric) Calibrated age 68.2% probability 1050AD (25.7%) 1083AD 1126AD ( 5.6%) 1136AD 1151AD (32.6%) 1192AD 1198AD ( 4.3%) 1205AD 95.4% probability 1043AD (36.0%) 1105AD 1117AD (59.4%) 1216AD 14C ages are reported in conventional radiocarbon years BP (before present = 1950) in accordance with international convention (M. Stuiver & H.A. Polach: Discussion of reporting 14C data. Radiocarbon 19(3) (1977) p. 355). Thus, all calculated 14C ages have been corrected for fractionation so as to refer the result to be equivalent with the standard δ13c value of -25 (wood). Reported δ13c and δ15n values have been measured by high-precision stable-isotope mass spectrometry. The values represent the isotopic composition of the original sample and is therefore useful for interpretation regarding association with the terrestrial/marine/freshwater food chains as well as trophic levels. Calibrated ages in calendar years have been obtained from the calibration curves in Reimer et al Radiocarbon vol. 55(4) pp by means of the Oxcal v4.1 calibration programme (Bronk Ramsey., 2009, Radiocarbon, 51(1) ) using the terrestrial calibration curve, IntCal13 (for marine samples, see below). The probability method has been used to calculate the calibrated age ranges corresponding to 68.2% probability (1 sigma) and 95.4% probability (2 sigma) with the probability of each range given in brackets (indicating the probability that the true date belongs to the interval in question).

13 OxCal v4.2.3 Bronk Ramsey (2013); r:5; IntCal13 atmospheric curve (Reimer et al 2013) 1100 Radiocarbon determination (BP) Calibrated date (calad)

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