In 1999 rescue archaeology revealed a Mithraeum at Güglingen. The temple was of stone, and oriented WSW-NNO, and measured 11m x 7.5m. The podia were 1.50m wide, and c. 60cm high.
According to German Wikipedia, excavations in the area continued from 1999-2005. A second, timber-frame Mithraeum was found. The site has been made into an open-air museum.1 However Mithraeum I has been reburied. The stone structure was built in the second half of the second century and existed until the 3rd century.2
Richard Gordon wrote a summary for the Electronic Journal of Mithraic Studies, which is reproduced here as the EJMS site is now heavily corrupt and the .doc file now inaccessible.3
Mithraeum in Güglingen, Landkreis Heilbronn (Baden-Württemberg)
A rescue dig of a few days (28.4-7.5.1999) had to be undertaken at short notice to investigate the remains of a Roman and Alamannic settlement on the 'Steinäcker' and 'Ochsenwiesen' areas just outside the town of Güglingen, SW of Heilbronn, that were about to be destroyed by clearing and draining work preparatory to the building of an industrial area on the right bank of the River Zaber, which runs to the S. of the town. The finds were so promising that it was decided that each parcel of land should be examined by the archaeologists before sale, to determine the nature of the site (villa rustica, vicus etc.). In July 1999 however two large parcels were sold by the town, necessitating a hurried examination of around 8 ha of ground (8.8 - 29.10. 1999). In one of these parcels, at the bottom of the slope down to the Zaber, a mithraeum was discovered (Fig. 1), the fourth to be found in Baden-Württemberg. The whole area is characteristically wet, and required constant drainage to carry water off the slope into the water meadows along the river.
The site lies directly on the Roman road that ran South of the line of the Zaber, and was well outside the Roman settlement. The stone-built temple (Fig. 2) was oriented WSW-NNO, and measured 11m x 7.5m. The podia were 1.50m wide, and c. 60cm high. The long side-walls were built directly onto the soft ground without any attempt at creating foundations. The eastern end of the temple could not be traced, and had apparently been partly dismantled by modern stone-robbers. In the excavator's view, the entrance may have been from the w.: the end wall there is virtually complete, but the outer wall (the threshold, presumably) was in places very worn (see below however). The building was roofed with tiles, and plastered within.
There seem to have been at least two building phases. In the first, the floor was evidently constructed of wooden boards. This building burned down and in the subsequent rebuilding steps were taken to deal with what had evidently been a major problem in the first phase, water seepage. A drain was built into the old floor along the foot of the S. podium, and two channels were cut into the floor of the central aisle to carry water off into this drain. At the end of the podium, the drain turned sharp l. and carried the water out of the temple at the NW corner, debouching about 6m away. A new floor was then constructed of carted-in soil, up to 20 cm thick. Perhaps connected with these works, a circular stone-lined cistern was built about 8 m. away from the mithraeum higher up the hill (Fig. 2), and fed by at least one shallow trench. To prevent the overflow water from descending into the mithraeum, a stone-lined overflow channel led the water in an arc past the W. end, again debouching into the valley bottom.
An unusual find may also have been connected with the problem of water-seepage: in the centre of the main aisle a circular pit about 1.5m in diam. and 1m deep was found, whose rim was secured with tamped stone rubble (Fig. 3). [Since this pit contained virtually nothing, it seems likely that it was a simple kind of sump for the first phase of the building, which was normally covered by the wooden floor and periodically emptied with buckets (hence the need to reinforce the rim). But a ritual use cannot of course be excluded. In the second phase, its function (if it was indeed a sump) was taken over by the drainage channels. The preliminary report however does not state whether it was dug below the first or the second floors, observing merely 'Ob die Grube ursprünglich zum Mithräum gehörte oder lediglich überdeckt wurde, liess sich nicht feststellen' (p.143). It is from this remark that I deduce that it must have been dug below the first, the wooden, floor.]
At a later point still, a secondary wall was built about 1m away from the 'threshold' (i.e. the W. end-wall) abutting onto the podia-walls. Between the 'threshold' and this secondary wall was a large block of stone, on end, that apparently acted as a step. Whether this is related to constant problems with damp is not known, and the whole W. end needs to be looked at again. [It seems to me that it is more likely that the W. end was the cult-niche end, and that this secondary wall was intended to create a more substantial platform for a cult-relief. It seems unlikely that a drainage-ditch was dug directly in front of the entrance. It also seems unlikely that a stone-built mithraeum had no entrance hall or pronaos of any kind, which we may assume was built onto the E. end. Against this is the fact that the outer W. wall was in places very worn, 'stellenwise stark abgetragen', though the excavation did not apparently reveal whether this wearing was due to its use as a passage rather than to the alterations associated with the building of the parallel wall. The function of the squared stone is hard to explain if this was indeed the entrance.]
No details are known. The preliminary report speaks simply of large quantities of recovered material, in particular a lot of pottery, iron and bronze objects, coins. A large quantity of small animal-bones had collected under the podia and in the drains. All this material has yet to be analysed.
A fragment of an altar-base was found half-way along the aisle by the S. podium wall, and on the opposite side a fragment of a small conical column. In the lowest level of the NW corner and somewhere along the l. podium wall, were found small broken cups, evidently dedicatory offerings associated with the erection of the first phase.
The building was destroyed finally by fire, at a date that cannot yet be determined. Quantities of tiles fell into the building, and later part of the S. wall collapsed (Fig. 1). A large sand-stone column-base was found lying over the cistern further up the slope away from the river. Inside the cistern were found half of a column-base, some other worked stones and altar-fragments, and the capital of a Jupiter column that had been badly burned. There may therefore have been a small sacred area here, of which the mithraeum was only one part.
Further digging over the whole site is projected for 2000.
Source: Walter Joachim, 'Ein römisches Mithräum mit römischen und alamannischen Siedlungsresten in Güglingen, Kreis Heilbronn,' Archäologische Ausgrabungen in Baden-Württemberg 1999 (Stuttgart, 2000), 139-43.
Sent me by the kind offices of Dr. Andreas Hensen.
Coordinates: 49° 22' 36" N, 8° 09' 08" E / 49.37667° N, 8.15222° E.4
Walter Joachim, "Ein röisches Mithraeum mit römischen und alamannischen Siedlungsresten in Güglingen, Kreis Heilbronn," Archaeologische Ausgrabungenin Baden-Wuerttemberg, 1999 (Stuttgart, 2000) pp. 139-143.
Gordon, Richard: "Mithraeum in Güglingen, Landkreis Heilbronn (Baden-Württemberg), Germany", EJMS, Volume I, 2000 (English, Zipped Word97) zip Unfortunately now corrupt.
Andrea Neth: "Fernab des Militärs: der vicus von Güglingen". In: Vera Rupp, Heide Birley (ed.): Landleben im römischen Deutschland. Theiss, Stuttgart 2012, ISBN 978-3-8062-2573-0, p. 99-102. (Reference from German Wikipedia)
Klaus Kortüm, Andrea Neth: "Römer im Zabergäu. Ausgrabungen im vicus von Güglingen, Kreis Heilbronn". In: Archäologische Ausgrabungen in Baden-Württemberg 2002, p. 116-121 (Reference from German Wikipedia)
K. Kortüm and A. Neth, "Roms Provinzen an Neckar, Rhein und Donau", Imperium Romanum 1, Stuttgart: Theiss, 2005. p.225-9, with figs 275-6. Review at JSTOR in JRS here.
German Wikipedia here. This states that the site was a vicus of some 80 houses, cobering 10 acres. The name of it is unknown. It was settled mainly by craftsmen. 30 houses, a baths, and 2 mithraea were excavated. It was settled around 125 AD, and abandoned around 250 AD and set alight. Alamanni occupied the site afterwards.
Also according to German Wikipedia: "Das Mithräum I, das 1999 ausgegraben wurde, ist heute wieder vom Erdboden bedeckt. Dieses Mithräum war das ältere derartige Heiligtum vor Ort. Der massive Steinbau wurde in der zweiten Hälfte des 2. Jahrhunderts errichtet und später noch verändert. Er existierte bis ins 3. Jahrhundert. Sein Kultraum war etwa 65 Quadratmeter groß."