Ragnar Saage

This study focuses on smithy and forge constructions in present day Estonia and Finland. The studied smithies can be divided into three time periods: pre-crusade Late Iron Age (11th-12th centuries); the age of transition (13th and 14th centuries), when foreign craftsmen settled in newly founded towns bringing their own traditions; and the 15-17th centuries, during which rivalry was established between rural and urban smiths. The most visible feature in the smithies-the forge-also changed during this period, evolving from a ground-level forge pit into a massive rectangular raised forge. The latter was adopted following the crusades and continued to be used until the 19th century.

During the investigations of Kohtla-Vanaküla, 140 spearheads or fragments of spearhead blades were collected. All spearheads from Kohtla are socketed and have a pointed-oval-shaped blade, only four examples are rhomboid. Based on radiocarbon dates the Kohtla spearheads most likely date from the Roman Iron Age. Kunda and Alulinna wealth deposits from northeastern Estonia contain spearhead assemblages most similar to the ones from Kohtla. The earliest finds of the main spearhead types found in Kohtla are known from Finnish Early Roman Iron Age contexts where this type prevails exclusively. The Finnish finds thus also correlate rather well with the dates obtained from Kohtla. The fact that Kohtla spearheads bear the greatest resemblance namely with finds from Virumaa province and coastal area of Finland indicates that they might come from these regions. However, the Kohtla spearheads are one of the earliest examples of such spearhead types in Estonia allowing to better refine the chronological distribution of this weapon type in the eastern Baltic. Additionally, we present the first metallographic analysis of a spearhead from this time period. The analysis shows that the spearhead was made out of homogeneous steel of good quality, whilst steel was used throughout the weapon and not only on the cutting edge. In comparison with the analysis of socketed axe from the same site, this might be seen as a testament to the higher status of weapons compared to tools.

This study analyses socketed iron axes of the first millennium AD. It was a widespread phenomenon that the first iron axes greatly resembled their Late Bronze Age counterparts. However, in northeast Europe, socketed iron axes continued to be in use far longer than in other parts of Europe. The Kohtla weapon and tool deposit contained about 100 axes, out of which one specimen was selected for invasive metallographic analysis. The axe was made from four separate components: firstly the bulk of the axe that had been made from a rolled tube; then the steel cutting edge; then also a wedge shaped filling in the blade; and a slag-rich filling in the socket. As the axe turned out to have undergone quite a complex forging technique, experimental production of the same type of axe was undertaken to better understand the reasoning behind the ancient smiths decisions. The experiment revealed that the two fillings served several purposes and that the choice of materials by the Iron Age smiths was well suited for the function of these parts. When the Kohtla axe was compared to the other axes, it became evident that the same results could be achieved with different forging patterns. In the future, the manufacturing technology could be the basis for improved typological and chronological characterization.

In this work we used non-destructive SEM imaging and EDS analysis to characterize the material composition of an Arabic finger ring, which was found in a 9(th) c. woman's grave at the Viking Age (A.D. 793-1066) trading center of Birka, Sweden. The ring is set with a violet stone inscribed with Arabic Kufic writing, here interpreted as reading "il-la-lah", i.e. "For/to Allah". The stone was previously thought to be an amethyst, but the current results show it to be coloured glass. The ring has been cast in a high-grade silver alloy (94.5/5.5 Ag/Cu) and retains the post-casting marks from the filing done to remove flash and mold lines. Thus, the ring has rarely been worn, and likely passed from the silversmith to the woman buried at Birka with few owners in between. The ring may therefore constitute material evidence for direct interactions between Viking Age Scandinavia and the Islamic world. Being the only ring with an Arabic inscription found at a Scandinavian archaeological site, it is a unique object among Swedish Viking Age material. The technical analysis presented here provides a better understanding of the properties and background of this intriguing piece of jewelry. SCANNING 9999:XX-XX, 2015. © 2015 Wiley Periodicals, Inc.

PRESENT-DAY ESTONIA WAS INCORPORATED into the Christian world in the early 13th century. This event brought dramatic changes to both its society and landscape, including the establishment of the first towns that soon played an important role in the emerging Hanseatic network, mediating trade between the West and East. These political and cultural changes are also reflected in the influences that reached Estonian towns, with the migration of craftspeople from German-speaking areas and Scandinavia; in particular, these innovations occurred in non-ferrous casting technology. The most important changes included the introduction of refractory crucibles, massive melting furnaces and more complex stone-casting moulds. Residue analysis showed evidence of highly specialised metalworking taking place. The large sample size revealed some unusual alloys, which are explained either by craftspeople's experimentation or by the reuse of scrap metal. By looking at the different crucible types an...

Mineviku metallitöö kuulub nende valdkondade hulka, mille uurimisel on arheoloogia märkimisväärseks teadmiste allikaks. Minu väitekirja eesmärk on anda peamiselt arheoloogilise leiuainese põhjal uut informatsiooni Eesti metallitöö kohta 7.–17. sajandini. Selle perioodi jooksul toimus nii tehnoloogilisi kui poliitilisi arenguid, millest kõige murrangulisemaks võiks pidada 13. sajandi alguse vallutussõda, mille käigus liideti Eesti alad kristliku Euroopaga. Uute linnade loomisega hakkas siia saabuma ka läänes väljaõppe saanud käsitöölisi, kes tõid kaasa omad töövõtted ja tööriistad. Põhilise allikana käsitlen metallitööpaiku ja sealt pärinevaid tootmisjääke. Rauatöö uurimiseks on suurema tähelepanu all sepikojad, seal asunud ääsid ja sepistamiseks vajaminev raud. Kohaliku rauasulatuse ja sepikodade laialihajutatud paiknemismustri tõttu säilitas maasepikoda oma rauaaegse ilme 14. sajandini. Eriti suure tähelepanu all on 14.–17. sajandisse dateeritud Käku sepikojaase Saaremaal, kuna sealt tuli 2007.-2014. aastal välitööde käigus välja nelja järjestikuse sepikoja ehitusjäänuseid kui hulgaliselt leide. Juba Käku kõige varasem, 14.–15. sajandisse dateeritud, sepikoda meenutab oma põhiplaanilt ja ääsi ehitusviisilt pigem 14. sajandisse dateeritud Haapsalu linna sepikodasid kui 13.–14. sajandi algusesse dateeritud Paatsa maasepikoda, mis viitab maa ja linnaseppade traditsioonide ühtlustumisest. Metallograafiline analüüs Käku sepikoja rauakangidest andis aga teavet selle kohta, et kuidas käitlesid sepad toorrauda ja taaskasutati terasest tööriistu. Metallivalu puhul analüüsisin eelkõige metallisulatustiigleid, valamiskulpe ja valuvorme ning neis leiduvaid metallijääke kasutades nii portatiivset spektromeetrit (pXRF) kui skaneerivat elektronmikroskoopi (SEM-EDS). Selgus, et nooremal rauaajal oli nii hõbeda kui tina valamine koondunud linnamägedele ja maalinnadesse. Uuritud tiiglikatketest sisaldas 27% hõbeda jääke, mis näitab, et hõbedavalu oli laialt levinud. Peale ristisõda ning uute linnade rajamist asendas linnades tehtud metallivalu varasemalt linnamägedel ja maalinnades tehtud käsitöö. Linnadesse tuuakse ka imporditud tiigleid, kus muude jääkide hulgas on puhta kulla valamise jäägid, mis on kontrastiks rauaaegsele metallivalule.

Archaeology can contribute greatly to our understanding of past metalworking. The main goal of this thesis is to provide new information on Estonian metalworking between the 7th–17th centuries, based on archaeological sources. During this period there were political changes and technological developments that impacted Estonian society. The most important event was the 13th century crusade, after which Estonia was brought into Christian Europe. Western craftsmen started to settle into Estonia with the founding of new towns, bringing new techniques and tools as they came. My main contribution is the study of metalworking sites and the analysis of their production waste. Smithies, forges, iron blooms and bars are all investigated to gain a better understanding of ferrous metalworking. Local iron production and the scattered locations of smithies retained the pre-crusade workshop layout up until the 14th century. The 14th–17th century smithy site of Käku was studied in detail and the excavations between 2007–2014 revealed the remains of four consecutive smithies and thousands of finds. The smithy of Käku more resembles the 14th century urban smithies at Haapsalu, than the 13th–14th century rural smithy of Paatsa, which indicates a convergence of rural and urban smithing traditions by the 14th–15th centuries. Metallographic analysis of iron blooms and bars from the smithy site of Käku provides insight into how the smiths processed bloomery iron and how steel tools were reused. The non-ferrous metalwork is studied via crucibles and casting moulds. The residue they contained was analysed with a portable spectrometer (pXRF) and a scanning electron microscope (SEM-EDS). The results show that in the 7th to early 13th centuries the casting of silver and tin took place at hill forts and strongholds. Silver residues were detected in 27% of the crucibles, which suggests that silver casting was common. After the crusade, the towns became the main centres for the casting and crafting that previously was undertaken in the fortified centres. Foreign craftsmen introduced imported crucibles that were more durable at high temperatures than crucibles made from local clay. A few of the studied crucibles had residues of pure gold, which indicates a higher level of specialist goldsmithing, compared to the work of pre-crusade craftsmen.

29 iron rings with diameters between 9 and 15 cm were excavated in 1989 at a Vendel Period settlement site with a longhouse, located at Åselby in Dalecarlia, Sweden. Most of the rings had between one and three smaller rings attached. Rings of this type and size are fairly common at Scandinavian Vendel and Viking Period sites – settlements, cemeteries and cult precincts – but their function remains debated. The rings from Åselby have been interpreted as iron/steel bars, to be used or traded as raw material for e.g. weapons production. Previous metallurgical analysis of one Åselby ring showed it to consist of somewhat uneven but still decentquality carbon steel. General conclusions should however not be drawn from a single observation. Here, we have sampled six Åselby rings for metallographic examination of the cross-sections. The material quality and carbon content of the sampled rings were found to be very uneven, and relatively large inclusions of unworked slag were common. We conc...

The purpose of this research was to try and determine the suitability of a portative X-ray fluorescence spectrometer (pXRF) for ascertaining the chemical composition of telescope mirrors in a non-invasive way. Both of the mirrors in question very probably date back to the early 19th century and were made by William Herschel and Johann Gottlieb Friedrich Schrader (although this is not 100% clear). One aim was to see whether the chemical composition of the objects was similar to what we know about the telescope mirrors of the time. The search for the perfect composition of a telescope mirror haunted telescope makers from the 17th century until the second part of the 19th century when silvered glass mirrors were developed by Leon Foucault and Marc Secretan. A mixture of copper and tin was used to make speculum metal with the addition of a variety of metals and other compounds to add strength and lustre to the telescope mirror. The results of the pXRF tests show both mirrors are similar...

Determining maximum heating temperatures of burnt bones is a long-standing problem in forensic science and archaeology. In this pilot study, controlled experiments were used to heat 14 fleshed and defleshed pig vertebrae (wet bones) and archaeological human vertebrae (dry bones) to temperatures of 400, 600, 800, and 1000°C. Specular component included (SCI) color values were recorded from the bone surfaces with a Konica-Minolta cm-2600d spectrophotometer. These color values were regressed onto heating temperature, using both a traditional linear model and the k-nearest neighbor (k-NN) machine-learning algorithm. Mean absolute errors (MAE) were computed for 1000 rounds of temperature prediction. With the k-NN approach, the median MAE prediction errors were 41.6°C for the entire sample, and 20.9°C for the subsample of wet bones. These results indicate that spectrophotometric color measurements combined with machine learning methods can be a viable tool for estimating bone heating temp...