Iin Illinsaaren keskiaikainen tinakannu

摘要

Iin Illinsaaresta löydettiin 1890-luvun puolenvälin tienoilla maatöiden yhteydessä tinakannu (Kuva 1), joka päätyi vuonna 1896 vasta perustettuun Pohjois-Pohjan-maan museoon. Kannu kirjattiin museon kokoelmiin pääluettelon ensimmäiseksi esineeksi, ja se on sittemmin säilyttänyt tuon statuksensa selviten niin vuonna 1929 museota pahasti hävittäneestä tulipalosta kuin vuoden 1940 tuhoisista pommituksistakin. Samalla tavoin on säilynyt muotokielensä perusteella 1300-luvulle ajoitetun tinakannun todistusvoima Iin ensimmäisestä keskiaikaisesta kirkosta, jonka ensisijaisesti tämän löydön ja sitkeästi paikkakunnalla elävän perimätiedon vuoksi3 on oletettu sijainneen Illinsaaressa.%A medieval tin jug (Figure 1) was found during excavation work on Illinsaari island in Ii in 1895. The following year, the tin jug became the first artefact to be placed in the collection of the Northern Ostrobothnia Museum. However, in terms of research, the Illinsaari tin jug remains relatively unknown. This article primarily examines the location where the tin jug was discovered as well as its context of use - that is, its relevance as evidence of the medieval chapel that, according to tradition, was located on the Illinsaari island. In addition, the article discusses the tin jug as proof of medieval goods traffic to Ii. The Illinsaari island is located in the middle of the main channel of the River Ii, approximately one kilometre east-northeast of the centre of Ii (Figure 2). This large, irregular island was formed when small islands, separated by narrow strait-like channels in the River Ii, were raised and merged. Some of the channels have since developed into small ponds. One of the ponds, Kellolampi, is mentioned as the location where the Illinsaari tin jug was discovered. According to tradition, Ii's first chapel was located by the pond. An inspection report prepared by Ahti Paulaharju after his expedition to Illinsaari in 1961 reveals the location of Kellolampi. At the time, Paulaharju worked as a curator at the Northern Ostrobothnia Museum. A note under the draft map (Figure 3A) in the report reads: "used to be a strait between a and b, incl. Kellolampi". This strait can be seen on a farm map prepared in 1904 (Figure 3B). On a basic map from 1955 (Figure 2), we can see that the arable area has expanded considerably to the southwest. In 1961, Kellolampi had probably ceased to exist as a water area. The topography of the area has since continued to change: located to the north-east of the strait, the Kaunistörmä bank and its surroundings were excavated to be used as soil in bridge construction in Ii. The northern part of the island was embanked in conjunction with the construction of a power plant (Figure 3C). The most probable location of Kellolampi is highlighted in this shaded image (Figure 3C), based on a digital elevation model. If the Illinsaari tin jug is from the fourteenth century, as has been stated based on its style, it was probably hidden in shallow water near the shore of the pond. Its excellent condition supports this assumption, as low temperatures expose alloys of tin and lead to tin plague, much like what happens with pure tin. For this reason, it is more probable that the tin jug has survived through the centuries in the pond or wetland rather than on dry land. The significance of the Illinsaari tin jug is related to its context of use, which may have been sacred or secular. Three arguments have been presented to support the sacred interpretation: the location of the first church in Ii on lllinsaari, the Golgotha motif on the medallion on the inside base of the tin jug and the Christ monogram scraped onto the knob on the lid. In terms of interpretation, the significant qualities of the tin jug can be considered to include its shape and size as well as the decorative medallions on its inside base and the lower surface of the lid: the former features a Golgotha motif, and the latter features a simple rosette. The rosette on the Illinsaari tin jug (Figure 4A) was shaped directly onto the casting mould, and similar floral motifs are typical of the lids of tin jugs, which makes them irrelevant in terms of determining the age of the tin jug. The motif on the inside base (Figure 4B) is recognisable based on its numerous equivalents: the Virgin Mary and John the Apostle standing beside the crucified Jesus. The mark on the top surface of the lid (Figure 4C) has been interpreted as being a Christ monogram or the ownership mark of a farm or farmer in Ii. However, it is not a traditional Christ monogram, a symbol combining the Greek letters chi and rho. Instead, it may be a combined rune based on runic characters, a variation of the "cross-crowned" Virgin Mary monogram. In any case, the purpose of the mark would be to indicate personal or collective ownership. Furthermore, drawing the line between the worldly and the sacred is not possible based on the archaeological context of the discovery of medieval tin jugs in Finland. Inventory lists of churches reveal that tin jugs were common artefacts. However, tin jugs preserved until our time are rare. No medieval tin jugs retaining their ecclesiastical context are currentlyknown to exist in Finland. Eight tin jugs have been discovered in seven locations (Figure 5) in Finland, but they do not constitute a whole that reflects their context of use. For this reason, it makes more sense to see the Illinsaari tin jug as evidence of early local affluence and trade connections and to subsequently ask where the Illinsaari jug was made and how much it cost. Tin artefacts brought to Finland in conjunction with Crusades and Hanseatic trade were initially rare and expensive merchandise. Judging from its shape, the most probable place of production of the Illinsaari tin jug was northern Germany. In addition, the thumb button of the tin jug has a north German double lens shape. However, the shape of the tin jug is not very indicative of its age: practically identical examples of this type of vessel were extensively produced from the fourteenth until the sixteenth century. It is possible to conclude the origin of the jug from its 1.75 litre volume. In medieval Sweden, a "jug" was 2.65 litres, whereas the volume of German jugs was typically 1.88 litres. The volume of German wine jugs was 1.82 litres. In other words, even the volume of the Illinsaari tin jug suggests a north German origin. The chemical composition of the metal in the tin jug was examined using a Bruker IV-SD X-ray fluorescent analyser at the archaeology laboratory of the University of Oulu. The results showed that the jug was made from a near pure alloy of tin and lead. The average composition of the metal corresponds relatively accurately to "three stamp tin" (Sn 83% , Pb 17%) in the three-category classification used in the seventeenth century. In 1694, its price was 13.33 silver öre per pound. The Illinsaari tin jug weighs 2.2 kg, which equals approximately five pounds in the seventeenth century. Consequently, its price can be calculated at approximately 66.67 öre, or 8 marks and 2.67 öre. This estimate indicates the price category: the sum is equivalent to what a paid worker earned in more than six months in the fourteenth century. In other words, on a more general level, the Illinsaari tin jug is reflective of the market potential generated by the salmon rivers in northern Ostrobothnia in the Middle Ages. In the fourteenth century, the area was within the sphere of interest of many significant powers. One indication of this is the Treaty of Nöteborg between Sweden and Novgorod in 1323. At that time, the Catholic Church organised an administrative hub in the north, seeking to strengthen its position in the coastal areas of the Gulf of Bothnia. This may be the background against which the Illinsaari tin jug should be examined. It is proof of centralised administration having reached northern Finland in the Middle Ages, enhancing the exchange and monetary economy.