Middelalderlige stenmortere i Danmark

Resumé

Medieval Danish stone mortars

Classification: The Danish medieval stone mortars may be classified according to material, which simultaneously provides a typological classification.

Group A: Mortars of calcareous sandstone.

AI: Yellowish-white, fine-grained and soft. Can be worked with a knife. (Fig. 1-6).

Group B: Mortars of limestone.

B I: Light grey limestone of very coarse heterogeneous structure with copious intermixture of snail shells. The chiselled surface has the appearance of a much­stained mirror, roughly like the surface of a piece of root-wood. In fresh breaks it has a greenish tinge. Very hard, and difficult to work with a knife. (Fig. 7-12).

B II: Schistous limestone. Grey stone of homogeneous structure. The surface exhibits layers of darker, lenticular particles. More diffuse small white particles are also present. Very soft, and easily worked with a knife.

B III: Light greyish-yellow limestone of porous surface and structure, with snail shells. Hard, and difficult to work with a knife.

B IV: Light yellowish-grey limestone of fine-grained homogeneous structure. Relatively hard, but can be worked with a knife. (Fig. 13).

B V: Whitish-yellow limestone of very porous structure with small snail shells. Softer than Group BI and B III.

B VI: Light grey limestone of fine-grained homogeneous structure. Relatively hard, but can be worked with a knife. (Fig. 14).

B VII: Dark grey limestone of very fine-grained homogeneous structure with lighter grey layers. At worn spots almost black. Strongly reminiscent of Belgian marble (Namur stone). (Fig. 15).

Group C: Mortars of sandstone.

C I: Grey homogeneous micaceous sandstone of irregular horizontal cleavage. Hard, but can be worked with a knife. (Fig. 16).

Group D: Mortars of soapstone (steatite).

DI: Coarse-grained Norwegian steatite. (Fig. 17).

Dating. None of the Danish stone mortars have been found in circumstances which permit accurate dating, and they cannot therefore be arranged in a chronological series. They seem, however, to date from the 13th to 15th centuries.

Foreign analogues. None of the mortars described above can be of local Danish manufacture. The lime- and sandstone employed is found on both sides of the English Channel -in England, northern France and the Netherlands- where these rocks are so common that a more accurate placing is not possible on a geological basis. Steatite is of Norwegian origin.

Stone mortars have been dealt with by G. C. Dunning in two publications (23 and 24). He recognizes three stones used in their manufacture - 1 Purbeck marble, 2 Burr stone and 3 Caen stone.

Purbeck marble comes from a quarry on the Isle of Purbeck off the Dorsetshire coast of southern England. It is a grey stone containing fossils of the freshwater snail Viviparus. It was used prolifically in the Middle Ages from the 12th century onwards in church building, pillars and capitals, and in sculpture.

Dunning remarks that the shape of the mortars seems to depend on the character of the stone. Purbeck marble mortars have a basin with straight or slightly curved sides and the edge may be plain with a flat top, or slightly thickened with circumferential grooves. They normally have four knobs at regular intervals around the rim and ribs often curve from knob to knob. Pierced lugs are foreign to the porous nature of the Purbeck marble, which is more suited to handle-like ribs or solid lugs. Dunning mentions five specimens with pierced lugs in this material, however, and sees this -with a few specimens on square bases- as the result of influence from mortars fashioned in Caen stone. The surface is either pecked or chiselled.

Burr stone is described as a yellow limestone with fossil shells. It is related to Purbeck marble but softer; the shapes are also normally softer. The sides of the bowl are more strongly curved. The rim is thickened with bevelled edges. The ribs and knobs are as in the Purbeck types, but pierced lugs are unknown.

Caen stone is described as a fine white limestone, quarried outside Caen in Nordmandy. It was also used as building material in the Middle Ages and was widely exported. The forms are characteristic: square base; bowl with curved sides; large, facetted, pierced lugs; and on the rim, which is flat and unprofiled, facetted knobs with V-shaped pouring channels. Judging by the illustrations, the surface is channelled or zig-zag chiselled in horizontal bands. Eight specimens are known from England and can be dated by context to the end of the 13th century, but is is remarked that Caen mortars have been found in the castle at Caen »in contexts of later date, which probably shows that the mortars continued to be made for several centuries« (29).

Two of the groups in the Danish material, the largest ones A I and B I, may be assigned without difficulty to the foreign groupings.

Within group A I, Dunning has identified one mortar as being of Caen stone, and the main forms of the group make such an assignation perfectly natural, although there are variations (no. 3 and 4) which depart from the shape of the typical Caen mortar.

Group B I mortars are undoubtedly of Purbeck marble. There are also many morphological features corresponding to those of the published Purbeck mortars, although only one of these is identical with Danish mortars (Dunning fig. 74 no. 1). The pierced lugs found in six of the Danish mortars may support Dunning's claim that Purbeck mortars were developed under the influence of the Caen mortars.

To the soapstone mortar there are two parallels in the museum at Trondheim (33).

The agreement between material and detail indicates that each group derives from one particular quarry or at least one particular region.

All the stone mortars found in Denmark have been imported. Of a total of 25 specimens, nine come from Normandy (or from northern France), seven from the Isle of Purbeck in southern England, one further specimen possibly from England, and one from Norway. Of the remaining seven, one possibly derives from Belgium, whilst the remainder can merely be placed in the regions bordering the English Channel.

Danish distribution. As far as the Danish distribution is concerned, 21 specimens have been found in Ribe, one at Søborg on northern Zealand, one on Sprogø, and one on Stagsevold near Vejle, whilst there is no provenance for the remaining one.

Conclusion. This distribution is another strong indication of the position of Ribe as the most important Danish trading centre on the North Sea in the Middle Ages. In this respect, the artefacts come to the assistance of the written sources. I have previously published a survey of the import of North Sea pottery into Denmark in the early Middle Ages, and could in this commodity too demonstrate the dominance of Ribe over the rest of Denmark (36). England played a remarkably minor role in the pottery trade with Denmark, and northern France and Belgium a surprisingly important role, but the parallelity in the testimony of the two groups of finds is otherwise considerable.

A warning was given in the above-mentioned publication, against putting too much reliance on the dominance of Ribe in pottery finds, because it would be easy to draw conclusions ex silentio. It is true that none of this pottery has been found in Copenhagen, and archaeological excavations in Århus, Viborg, Odense, Ålborg, Svendborg and Kalundborg have only yielded a few specimens, but too few of our medieval towns have been studied to date, and the interest in a mere collection of material on building sites has been too small for final conclusions to be drawn. Mortars or mere fragments of mortars will be more likely to find their way into the museums than pottery, and although they represent a much smaller body of material, they are therefore a better indicator of trading routes and Danish commercial contacts in the Middle Ages.

Mogens Bencard