Aerial Archaeology in Slovakia

The main target of the Slovak part in the project is Danube region in the territory of Slovakia. The Danube, Europe's second largest river, meets the territory of Slovakia by its middle part – from the Ipež estuary (at km 1708.2) to the Moravia estuary (at km 1880.2), measured from the Danube's estuary into the Black Sea. Although this is a relatively short stretch of border (172 km), the Danube is Slovakia's main river artery. It drains almost all of the country's area, directly or through the river Tisa.

The goal of the project is to examine the process of the formation of settlement structure and historical cultural landscape on this territory in particular periods of prehistory up to the Middle Ages, based on systematic use of non-destructive archaeological methods. These comprise the synthesis of aerial photography, surface prospecting, geophysical survey, use of environmental data and constituent eco-parameters in GIS environment, and modelling of the landscape at the level of selected micro-region/regions. The evaluation of obtained information will serve for the reconstruction of historical landscape in different time periods and it will help in effective protection of archaeological monuments.

In addition to its dominant hydrographic role the Danube has had great economic and cultural significance since ancient times, as prehistoric and early historical settlement concentrated on the river banks. Geographical conditions of settlement along the Slovak section of the Danube flow changed several times. On the basis of the relief and type of the landscape we can determine three areas: the area of Bratislava, the area of Vežký ýitný ostrov, and the area which stretches from the Danube's confluence with Váh to its confluence with Ipež.

The region of Bratislava played an important role mainly in prehistoric times, mediating impulses and contacts from the more advanced cultural centres of southern and south-eastern Europe. It was a place where two distant roads crossed: the trans-European north-south, so called Amber Road, and the transcontinental Danubian-Rhinish Road, which connected the east with the west. This relevant geographic position was the reason why Bratislava territory was densely settled as early as in the prehistory. The only part of Slovakia situated on the right bank of the Danube lies here, and includes boroughs Petržalka, Rusovce (ancient Gerulata), Jarovce and Čuňovo. In the Roman period this area was part of the province of Pannonia.

The main problem of conducting the project in Bratislava is that the area is built-up, particularly in the north and west. Thus new discoveries are mostly made in marginal areas used for agriculture. Only to small extent they stretch into the area of Žitný ostrov in part Podunajské Biskupice, where we have recorded a possible Roman marching camp, or a buried medieval village with enclosure.

Particularly interesting and important is the second area – Žitný ostrov. Žitný ostrov (meaning Rye Island), also called Veľký Žitný ostrov (Great Rye Island), is a river island in south-western Slovakia. It lies between the Danube and its tributary the Little Danube, and forms a major part of the Danubian Flat. It is the biggest river island in Europe with an area of 1,886 km², and is 84 km long and 15-30 km wide.

The territory of the island is flat, the highest point being 134 m above sea level and the lowest 105 m. Settlement from different periods can be observed from the height of 108-109 m. The character of Žitný ostrov was radically changed at the end of the nineteenth century by the regulation of river flows and by land amelioration. Originally, many tributaries of the Danube had flowed through the island, forming natural borders between villages or groups of villages, which thus formed independent territorial segments. However, these were not permanent but were modified by the frequent changes of the flow of the Danube and its tributaries.

Importance of Žitný ostrov for the settlement history and development of the relevant part of southern Slovakia has not yet been adequately appreciated. Already K. Willvonseder (Barta - Willvonseder 1934) stated that there did not exist any work dealing with the settlement of this region. In those days only several sites were known and six of these are mentioned by J. Eisner (Eisner 1933), plus some references in older Hungarian literature, mostly in Archeológiai Értesí­tö. K. Willvonseder sees the reason of this lack of interest in the Žitný ostrov area first of all in the fact that the territory was often inundated and swampy in the past and therefore considered unsettled. Not even after 70 years of research is our knowledge of the settlement of this area sufficient, and comprehensive work is still missing. This is certainly a handicap as it concerns a large area of 1,886 km². Various research activities confirmed that Žitný ostrov had been settled in the past, but little interest in more consistent explorations has persisted mostly due to limited results. The exact number of archaeological sites on Žitný ostrov cannot be determined without a more detailed data elaboration. Wider information on the settlement, however, has been obtained by elaboration of private collections. One of the latest published, which completes the picture of the settlement on Žitný ostrov is the collection of Antal Khã­n, which has become the basis of archaeological collections deposited in the Žitnoostrovské Museum in Dunajská Streda. The collection includes archaeological finds from field surveys on 22 sites, mostly from the regions of Šamorã­n and Dunajská Streda (Pichlerová - Tomčá­­ková 2001). More than 100 sites dated to various historical periods have been found recently and documented by typical methods. Based on existing information we can state that the settlement of Žitný ostrov was relatively intensive in almost all historical periods from the prehistory up to the Middle Ages.

The complex hydrogeographic conditions were the reason why aerial prospection did not provide expected results for a longer time. Fieldwalking has revealed that as a consequence of multiple alluvium, especially prehistoric sites are often situated as deep as 1.5 m below the current surface, which makes their discovery by classical archaeological methods such as surface collecting, impossible (Cheben - Kuzma - Rajtár 1982). The territories lie in the chernozem belt on the alluvial soils with gravel subsoil, which requires particularly favourable conditions for aerial archaeology. Such conditions existed in 2000, 2008 and 2009, when more than 80 new sites were photographed on several flights.

The third of the regions mentioned above is the area between the confluence of the Danube and Váh (km 1766) up to its confluence with Ipeľ (km 1880.2). Within this area, places where archaeological sites are situated can be relatively well determined according to their height above sea level (which is not always possible in the Žitný ostrov region). Settlement in this area can be assumed from 108-109 m above sea level, which has been also documented by surface explorations. Archaeological sites in the area between Komárno and Chľaba were found directly on the Danube bank in Iža, Patince, Kravany nad Dunajom, Moča, Mužla-Ìenkov, Štúrovo and in Chľaba (there is no such case in the area of Žitný ostrov). Besides, traces of settlement were found also under silts of the Danube, and in the Žitný ostrov area, e.g. in Komárno-Veľký Harčáš, where the Roman settlement appeared rather deeply under the recent surface and was covered with 1-1.4 m high silts (Rajtár-Roth 1982: 231).

SELECTED RESULTS

Temporary Roman camps

Significant contribution of aerial photography is that it supplies new evidence and knowledge of the Roman military presence on the territory of south-western Slovakia. For a long time only one Roman castellum was known north of the Danube in Iža near Komárno. Although the existence of short-term Roman military camps has been presupposed here, they were not discovered before the area was surveyed from the air. At present, 12 reliably identified Roman temporary camps in the Danube region are recorded in Iža – 5; Radvaň nad Dunajom/Virt – 4; Mužla - 2-3; Chotàn – 1, and so far the only one on Žitný ostrov in Hviezdoslavov. Besides the confirmed ones there might be others in Jičov, Chotí­­n and other locations, which have to be confirmed and verified.

Circular ditch formations

Several ditch-like formations of various kinds were found also in the Danube region. Most of them are not roundels, but circular ditches of different functions. A Lengyel-culture circular enclosure was discovered only in Bajtava. In 2004, geophysical measurements were carried out here, which proved two ditches with dimensions of 188x130 m and 150x115 m. This is a non-standard type of circular enclosure, where the outer ditch is rather oblong than circular or oval (Kuzma - Tirpák 2005). A circular ditch that could be possibly classified as a roundel was detected in the Svodí­n cadastre (Svodí­n 3) in the distance of perhaps 6 km from the enclosures in Svodí­­n 1 and Svodí­­n 2. Other discovered circular formations reach dimensions from 6 to 30 m, e.g. Bratislava-Podunajské Biskupice; mainly circles with the diameter of perhaps 6 m are quite common. Bigger circles – from 30 to 40 m – are in Mad and Mostová; their dating as well as their function are unclear so far.

Burial mound complexes and burial grounds

In western part of Žitný ostrov, in the circle of around 30 km from Bratislava, several burial mound complexes from the Hallstatt period have been revealed and some of them also excavated in recent past. The exact number of burial complexes is not known, as majority of them has not been observed on the earth surface. In the burial mound complex from the Hallstatt period in Dolné Janí­ky were found, together with three already known preserved burial mounds, traces of other 40-50 mounds destroyed by ploughing. Further burial grounds were documented in Čukárska Paka, Dunajská Lužná (3), Pusté Êľany, and other sites. The most spectacular discovery is a complex in Kostolné Kračany with around 40 burial mounds, while more of them undoubtedly exist on the adjacent field. 

Very important are discoveries of flat burial grounds, of which we have a very good example in Bratislava- Rusovce. In 1996, a burial ground of about 100 graves was discovered by aerial prospection. Thus we were able to prove the necessity of archeological excavation, since construction of family houses was planned for 2002. The excavation took place in 2002-2003 and over 160 graves from the Migration Period were excavated (Schmidtová - Weberová 2004). Without the results of aerial prospection this largest 6^th century burial ground in Slovakia would be destroyed in construction works.

The micro-region with the greatest number of burial grounds found in aerial prospection so far is the neighbourhood of Mužla and Štúrovo, where seven burial grounds have been documented on the Danube terrace in the length of 15 km. At the same time the region of Mužla and Štúrovo is most flown. We know more then 80 sites in its surroundings, of which 50 were revealed by aerial photography. Newly found cemeteries from the Avar Khaganate period are particularly relevant. Two of them (Mužla-Jurský Chlm 2 and Štúrovo-Obidská pusta) were also proved by excavations (Kuzma, I. 1996, 1997), and they have completed the recent knowledge on their occurrence in the wider area of Štúrovo-Obidská, where their number increased to five. The region of Štúrovo-Obidská thus appears to be another centre of Avar settlement similar to that in Komárno, where seven burial grounds from this period have been revealed recently.

Long Houses

One of the most significant new findings in recent years is a big group of sites with various structures with oblong ground plans and rounded corners, 5-7 m wide and up to 40 m long. In some cases we can observe their division into two spaces. They are situated on dunes or elevations mostly in the surroundings of the Little Danube and its tributary Čierna voda, but generally on the whole area of Žitný ostrov. At present we register more than 30 places of such ground plans in Veľké Blahovo, Horné Saliby, Zlaté Klasy, Čierna Voda, Tomášov, Tomášikovo, Jelka, Jahodná, Orechová Potôň, etc. In several cases they are relatively dense agglomerations of ground plans, e.g. in Komárno- Nová Stráž. The first, and so far the northernmost ground plans of this type we recognized in 1994 in Komjatice, where approximately 20 of them are situated on sand dunes. As their dating was unclear, the excavations were carried out in 2000, with the goal to confirm the dating of these objects and thus contribute to their interpretation. Considering the small number and unclear character of excavated finds, the structures were dated only generally to the prehistory and their interpretation is still open (Kuzma 2002). Surface collection on Žitný ostrov did not give satisfactory results either, which is likely due to the aforementioned alluvium. Nevertheless, analogies give us the right to suppose they could belong to the Neolithic and thus represent a new type of houses. Huts of similar shape in the vicinity of circular structures were excavated also in Dvory nad Žitavou, in Hungary on the area of Malý Žitný ostrov in Lébény near Györ, and also photographed by O. Braasch near Abda.

Historical maps

Historical maps have always been a priceless source for historians, historical geographers and archaeologists. Their expressive value being high, the maps provide possibilities for application of several methodical approaches, e.g. they are important components in creating archaeological predictive models.

We can see that the connection of historical maps to remote sensing, such as aerial prospection, satellite photography or LIDAR, represents a significant contribution to their exploitation. The maps contain information about land use (forests, agricultural land, settlements, etc) as well as about significant military structures (particularly maps from the military mappings). They also provide information, both direct and indirect, about archaeological structures, many of which can be confirmed by aerial prospection. They include structures visible in the landscape, such as prehistoric and medieval fortresses, burial mounds, and others. However, due to various factors the recorded data may be inaccurate. In contrast, the aerial photograph is a precise record of the existing state, and only the interpretation of its content can be inaccurate. In favourable cases the structures on aerial photographs can be identified and in turn the map data can be corrected. By means of aerial prospection we can also verify those features which are recorded but not specified in the maps. These are particularly burial mounds, marked mostly as elevations. In some cases they are marked in specific style, but their explanation is missing from the map legend.

On maps we find small medieval earthworks, which are referred to as “Sancz“ or “Alte Schanz“. One of such earthworks is Csillagvár in Dolné Janí­ky from the 17^th century. Medieval fortification elements found on maps are mostly around towns, where they form part of the town fortification or serve as systems of forward fortifications. However, with the development of cities they were mostly destroyed, and can only exceptionally be verified by aerial prospection.

Such an exception is Komárno, a unique example of fortification architecture of the 16^th to 19^th centuries. At that time it was the largest and strongest fortification system of the Austro-Hungarian monarchy, built in connection with Napoleonic wars around the original fortress on the confluence of the Danube and river Váh, and planned for a 200,000-strong garrison. In 1809 was built a forward temporary fortification line consisting of six redoubts connected by ramparts, placed approximately 3 km outside of the central fort, and called the “Palatine line“ (Gráfel 1986). In years 1839-1847 it was replaced by a defensive chain of five bastions of Neo-Prussian type made of solid building material, and the temporary line was removed and levelled off. In 1995, during documentation of the present state of the Komárno fortification we managed for the first time to photograph a part of the Palatine line and two of the six redoubts on its northern end (Hanzelyová - Kuzma - Rajtár 1997). The line can be observed on the maps of the second and third ordnance survey.

The largest fortification system has been found in Štúrovo-Obidská. In 2000, aerial prospection detected an extensive medieval earthwork running in the length of 1,900 m from its eastern end (Kuzma - Blažová - Bartá­k - Rajtár 2001). It appeared as positive crop marks. In 2005 and 2009 we also photographed the closure of the fortification in the west, so that its entire length was now 2,800 m. In 2010, we obtained from the firm Eurosense an orthophoto with 25 cm resolution, taken on 14 June 2009. The fortification is visible in its eastern part, but compared to our photographs of 25 May 2009 it is slightly less clear.

On the map of the first ordnance survey (and on other military maps) the fortification is not included. It can be seen for the first time on Matej Bel's map of Esztergom county (Mappa Comitatus Strigoniensis, Methodo astronomico geometrica concinnata) made around 1740 by Samuel Mikovà­ni, where the fortification is drawn and corresponds to our findings. Since forty years had gone between Mikovà­ni's survey and the first ordnance survey, a possible explanation could be that the fortification, which did no longer fulfil its original purpose, was levelled probably due to the use of agricultural land, and thus has not been preserved.

The fortification had been a part of the fortification system which served for defence of Esztergom during the Turkish wars. The Turks conquered Esztergom in 1543 and built up a bridgehead on the other side of the Danube.

BIBLIOGRAPHY

Barta, H. - Willvonseder, K. 1934: Zur ur- und frühgeschichtlichen Besiedlung der Grossen Schütt. Sudeta 19. Reichenberg 1934, 1-22.

Eisner, J. 1933: Slovensko v pravûku. Práce Učené Společnosti Šafaříkovy v Bratislavě 13. Bratislava 1933.

Gráfel, Ž. 1986: Pevnostný systém Komárna. Bratislava 1986.

Cheben, I. - Kuzma, I. - Rajtár, J. 1982: Výsledky prieskumu v oblasti sústavy vodných diel na Dunaji. AVANS 1881, 1982, 98-103.

Kuzma, I. 1996: Pohrebisko z obdobia avarského kaganátu v Štúrove - Obidskej pustatine. AVANS 1994, 1996, 114-115.

Kuzma, I. 1997: Pohrebisko v Štúrove-Obide. AVANS 1995, 1997, 115-117.

Kuzma, I. 2002: Výskum v Komjaticiach. AVANS 2001, 2002, 92-95.

Kuzma I., Blažová, E. – Bartá­k, M. – Rajtár, J. 2001: Letecká prospekcia na Slovensku, Archeologické výskumy a nálezy na Slovensku (AVANS), 2000: 112-138.

Kuzma, I. - Rajtár, J. - Tirpák, J. 1996: Zisåovacá­­ výskum v Mužli - Jurskom Chlme. AVANS 1994, 1996, 116-119.

Kuzma, I. - Tirpák, J. 2005: New Neolithic enclosures from Slovakia. In: 6th International conference on Archaeological Prospection. Proceedings, Extended abstracts, Roma, 13-16.

Pichlerová, M. - Tomčá­­ková, K. 2001: Archeologické nálezy zo Žitného ostrova, zbierka Antala Khá­­na. ZSNM XCV, Archeológia 11, 2001, 111-134.

Rajtár, J. - Roth, P. 1982: Zisåovacá­ výskum v Komárne-Veľkom Harčáši. AVANS 1981, 1982, 227-233.

Schmidtová, J. - Weberová, B. 2004: Pokračovanie výskumu na pohrebisku z doby såahovania národov v Bratislave-Rusovciach. AVANS 2003, 2004, 169-170.