Inland Navigation

Summary
Research on Mediaeval Inland Harbours between
Rhine and Danube
This paper presents ongoing and completed research within the framework of the
„Inland Harbours Project“ at Jena University. Five case studies – Karlburg, Salz,
Ratisbon, Frankfurt on the Main, and the Fossa Carolina – illustrate how archaeological, geo-archaeological, and historical methods can help to identify harbour structures
and historical riverbanks as well as transport networks. Previous work on mediaeval
navigation was usually focussed on maritime harbours as well as early mediaeval
emporia and often lacked interdisciplinary approaches. Because inland waters and
especially rivers may have changed their course dramatically throughout history,
it is essential to combine archaeological and historical methods and sources with
geo-archaeological and other natural scientific methods. This enables the accurate
reconstruction of the historical terrain relief and hydrological situations and correct interpretation of potential archaeological features of harbour installations. Additionally,
the meaning and function of a harbour can only be understood by studying its location
on a local scale within its related urban topography and harbour-related infrastructure
(e. g. castles), and on a regional and superregional scale within its topographical and
political framework. Research within the „Inland Harbours Project“ shows that even
in the High and Late Middle Ages, harbours did not necessarily need constructive
installations to land boats, which leads to the question of whether bank revetments
and quays were initially a response to land reclamation.
The two early mediaeval centres of Karlburg on the river Main and Salz at the
Frankish Saale illustrate how methods of archaeology and geo-archaeology can be
combined to receive evidence-based results of the former river courses and the terrain. For Karlburg, the hypothesis of a mediaeval harbour basin, which is based on a
historical map from the 19th century, has been revised. The results of archaeological
excavations, geological drillings, and surveys allowed the location of the mediaeval
river bank at a distance of 2 km up to 100 metres west of the modern river. Because no
harbour constructions were found, a natural landing site can be assumed. In contrast
to Karlburg, a wide range of geo-archaeological methods showed the stable position of the Frankish Saale in Salz from the Neolithic to the Early and High Middle
Ages. Being part of the royal palace complex Salz, located in the deserted riverine
settlement Mühlstatt, people lived on an elevated, flood-safe position on a calcitecemented gravel layer/alluvial fan. A simple, naturally formed landing site with a
gently sloping embankment could be reconstructed.
The ongoing research of the mediaeval harbour in Ratisbon is focussed on the
analysis of different small rescue excavations along the modern river bank and the
analysis of a huge urban excavation at Regensburg „Donaumarkt“. Because of the
excellent preservation of archaeological features, many scientific methods such as
dendrochronology, radiocarbon dating, archaebotany, and archaeozoology are used
to analyse the development of the mediaeval waterfront in light of inland navigation
Forschungen zu den mittelalterlichen Binnenhäfen zwischen Rhein und Donau 245
and urban development. Early results of the Donaumarkt excavation revealed that
the river bank from the 9th and 10th century was located 20 metres further inland.
Moreover, a navigable side arm or canal was detected parallel to the main arm of
the Danube that was used until the 11th or 12th century. In contrast to Karlburg and
Salz, different types of bank revetments have been documented such as wattle work,
stones, and wooden poles. The whole Danube river bank was used for navigation and
may have had special functional zones that were associated with the landward urban
topography.
An exceptional example for the construction of mediaeval inland harbours is a
quay wall of the 13th/14th century that was discovered in 2012 at the mediaeval Saalhof castle in Frankfurt on the Main. The quay made of stone and wood is located at the
court wall of a mediaeval water castle from the 12th and 13th century (the Saalhof).
The quay is two metres wide and paved, and it ran parallel to the court wall of the
Saalhof. Based on urban topography, the Saalhof castle was located in the commercial
heart of the town, framed by the most important streets. The Saalhof castle worked
as a seat of royal and later civil administration. Because of its location on a natural
alluvial land tongue that reached several metres into the river Main, it was suitable for
controlling navigation and trade. With regard to the water castle of Kaiserswerth on
the Rhine, the function of water toll collection is discussed. Mediaeval castles seem
to have been of great importance to delineate royal territory and to control and defend
important trade routes for inland navigation.
The rivers Danube and Main remain among the most important routes for inland
navigation today. Attempts to connect both river systems to bridge the European watershed were carried out in the Early Middle Ages by Charlemagne in 793 AD, who
initiated an ambitious canal project – the Fossa Carolina. Written sources describe
building the canal in detail as well as its failure. The constructive details of the threekilometre long canal and the question of its completion are the focus of an ongoing
project, „Fossa Carolina“, which combines archaeological and geo-archaeological
methods. Fieldwork showed that huge parts of the canal were buried under colluvial
sediments shortly after the digging, and they were never removed afterwards. Together
with the canal’s missing southern connection to the river Altmühl, this suggests that
the canal was really never finished. However, at least some parts of the approximately
five-metre wide canal fairway were ready to use and may have been navigable. The
banks of the canal were fixed with wooden embankments to prevent erosion. The
shallowest water depth was approximately 0.5 metres, which would have allowed
navigation by early mediaeval flat-bottomed ships.

Highlights

- We re-investigated the timbers of three Roman ships excavated along the Dutch limes.
- We used the content of the tree-ring repository DCCD to determine wood provenance.
- We created a natural distribution map of oak to interpret geographical results.
- We show that the ships were built in the lower-Scheldt region of Gallia Belgica.
- Inland navigation routes connected this region to the limes of Germania inferior.

In this poster the authors would take stock of the situation about three crucial pieces to understand how commercial and cultural exchanges were led across the inland water of the region of Piedmont during a large period of our history. These three pirogues are actually hosted in a renewed diorama in the Museo di Antichità di Torino and finally are exposed to the public in a way that enhances their understanding. Thanks to the recent renovation works in the museum and this new out-fitting for the pirogues, it was possible to make again wood and 14C  analysis, but unfortunately samples were too much contaminated by the wood treatments made during the ’80. In this poster some constructional details are easy to appreciate thanks to HD PhotoShooting.