1
2
2
1
2

MANCHING
During its heyday, from about
300 to 40 BC, the Celtic oppida civilization extended over all of
Central Europe, from Spain in the west to the Carpathian Basin in the east. One of the largest settlements of the time was the oppidum of
Manching in modern Bavaria. The
Celtic civilization eventually declined in the wake of the Roman occupation.
Large amounts of Celtic pottery as well as bronze objects, fibulae, glass bracelets and coins have been found all over Europe. The pottery is considered as an indicator of the socioeconomic situation of the Celtic oppida culture. Its uniformity indicates a common culture with extensive trade relations and a uniform style and technology of pottery making. The reasons for this are of much archaeological interest. Mössbauer spectroscopy is an efficient method of studying ceramic production techniques, reflecting both the properties of the raw materials and the ancient production and firing techniques. A comprehensive Mössbauer study of Celtic ceramics has therefore been undertaken, of which some aspects will be described here.
More details can be found in two volumes of the journal Hyperfine Interactions (Mössbauer
Spectroscopy in Archaeology, Volume I and II, Hyperfine Interactions 150 (2004) and 154
(2004), and in
R. Gebhard und U. Wagner, Das wirtschaftliche Umfeld von Manching: Möglichkeiten von Keramik-Untersuchungen. Kolloqu. z. Voru. Frühgesch. Bd. 7, 2002, 243-252.

The main types of Celtic mostly wheelturned pottery are grey (W) , painted (P), graphite (G) and coarse
(C) ware. Since no ancient unfired clay was found during the excavations, we used misfired sherds, mudplaster and technical ceramics for comparison as local materials.
More than 1400 specimens were first classified by neutron activation analysis. Cluster analysis of the trace element concentrations yields a classification reflecting the find spots, indicating that pottery was mainly produced locally rather than being traded over large distances. A principal component plot for two groups of graphite ware from the area around
Manching, one from Württemberg and one from
Modlesovice in Bohemia are shown on the right.
One specimen from Bohemia falls into the
Manching cluster and hence seems to stem from
Manching.

RT
RT velocity mm/s
RT
On the left a sherd of painted pottery is shown, together with the Mössbauer spectra of the brown pigment
(Fe
2
O
3
), the grey core of the sherd with a substantial amount of Fe 2+ indicating reducing firing, and the completely re-oxidized exterior layer below the layer of pigment.
On the right two sherds of black ceramics from different locations are shown together with their Mössbauer spectra.
The sherd from Manching contains only Fe 2+ , much of which is hercynite. The sherd from Bopfingen was reoxidized at the end of the firing cycle.
Manching
1 mm velocity mm/s
Bopfingen
1 mm

Graphite Ware
Modlesovice
Graphite Ware
Manching
B=0T
RT
19/651 19/429
B=0T
RT
B=0T
4.2K
B=0T
4.2K
B=6T
4.2K
B=6T
4.2K
velocity mm/s
Graphite ware was made of clay mixed with ground natural graphite that occurs in various locations in the east of the Celtic world. It was fired reducingly at temperatures around 800 ºC, but often re-oxidized during cooling, which sometimes (Modlesovice specimen) resulted in a high amount of the spinel phase maghemite (γ-Fe
2
O
3
). This can be unambiguously detected by
Mössbauer spectroscopy in an external magnetic field. In other cases, most of the Fe 3+ is contained in an amorphous silicate phase (Manching specimen).

Celtic gold coins were struck from blanks produced by alloying the gold with silver and copper in the pits of ceramic coin moulds. The coin moulds were inserted into a bed of hot charcoal and heated from above with blow tubes and bellows. Many used coin moulds have been excavated. The Mössbauer spectra of the top layer, the core and the bottom of such moulds show that only the top reached the melting point of gold. This was confirmed by field experiments using replica coin moulds with embedded thermocouples permitting the actual measurement of the temperatures.

In 1995 a huge Celtic pottery kiln with a well preserved flue plate and firing chamber was excavated in Lower Bavaria, the flue plate having a diameter of 1,3 m and a thickness of 0,1 m. It was of archaeological interest to find out what temperatures had been reached in the kiln. For a Mössbauer study, samples from the flue plate were compared with local loess site fired in the laboratory .
This comparison shows that the temperature in the flue plate nowhere exceeded 400 °C in antiquity. Probably the firing channel on the right, which was found collapsed, had failed already during the first effort to fire the kiln and the project was then abandoned.
Our long-standing study helped archaeologists to form a general picture about the extent of long range trade in Celtic Europe. While precious goods like glass bracelets and coins were traded over long distances, pottery was produced locally and generally not transported more than 50 km. On the other hand the uniform appearance of the Celtic pottery shows that information on the style and production were well spread all over Central Europe. The idea traveled, not the product.
Many thanks to all who have contributed to this study with their ideas and samples.