The Castle in the Middle of the Danube

 MAGYARUL

Spielberg castle on the Danube / Litography of Jacob Alt

It's not necessarily the Inség (Hunger) stone at Budapest that comes to mind when talking about rocky islands on the Danube, but rather the Babakai cliff on the Lower-Danube, or Jochenstein on the German-Austrian border. There were also island forts on the Danube, Ada Kaleh was perhaps the finest example, with its ramparts and bastions almost occupying the entire island on which it was built, until it was sunk by the "progression". However, there is another island in the Danube that fulfils both criteria, a rocky promontory and a castle, built in the middle of the Danube. Today, Spielberg's castle is a little difficult to find; it has been moved from the middle of the Danube by river regulation and is hidden in the middle of a riverine forest on the left bank of the Danube at river km 2116, opposite to the town of Enns in Austria.

 Ruins of Spielberg in 1840. (W. Mossman, W.H. Bartlett)

Spielberg castle on Matthias Vischer's engraving, 1674 (source)

Spielberg castle in 1650., sr. Matthäus Merian's engraving (source)

Without the river regulation works, it could be a true castle for hydrologers, ideal for landlords exploring the Danube, as an icebreaker fixed point in the middle of the ever-changing floodplain archipelago between Linz and Mauthausen. On the slower-flowing stretch behind the granite cliff jutting out of the riverbed, gravel bars, sandbanks and islands have formed and transformed after each flood, taking on a new shape. The Danube's turbulent, swirling course over the smaller reefs made navigation in the northern tributary difficult, as did the construction of the castle. 

Originally, Spielberg's granite cliff may have been closer to the right bank of the Danube, as evidenced by the Roman archaeological atrifacts found on it. The legionary camp of LAURIACUM at the mouth of the river Enns, where the veteran Roman soldier St Florian was pushed off the bridge with a millstone around his neck, was situated opposite. The discovery of Roman relics is no less sad a story, as the 1940/41 excavation season was carried out by prisoners from the Gusen concentration camp, a part of the Mauthausen Lager. Prior to that, in the 1930s, in keeping with the spirit of the times, the courtyard of the ruin had been the site of so-called knightly ceremonies held by local Nazis.

The Enns estuary and Spielberg Castle in the middle of the river (drawn by Charles de Feignet)

Spielberg Castle is almost a thousand years old, the earliest part of it dating back to the first decades of the 12th century. It was probably already on an island in the Danube when it was built, as its owners used it primarily as a castle of refuge rather than a residence. In times of war, this impregnable fortress was used by its lords as a refuge for their families, treasures and other valuables. Perhaps that is why its owners treated it like a hot potato, its first half-millennium of history being one of constant changes of ownership. It has been privately owned, owned by ruling families, the Babenbergs, the Habsburgs, and has been owned by various ecclesiastical estates, of which Regensburg was perhaps the most distant, with St Florian's monastery the closest. In 1619 it was a Danube toll-house, but the inhabitants of the castle were fond of plundering Danube sailors shipwrecked on the granite cliffs. Interestingly, the destruction of the castle was not due to siege, fire or frequent changes of ownership, but to the neglect of the longest-standing Weissenwolff family, who owned the castle and later its ruins until 1961. 

The oldest part of the castle is the late Romanesque tower, originally five storeys high, which was added two storeys higher in the early 1500s when the outer castle wall was built. The age of the engravings in the entry can also be determined from the collapsed roof structure in 1840. The best preserved part of the castle is the outer castle. A forester still lives here and carries out basic maintenance work.

The castle on the 1st military survey (1773-1781)

The castle on the 2nd military survey (1809-1818)

The castle on the 3rd military survey (1869-1887)

Parallel to the gradual destruction of the castle in the 18th century, a process was taking place in the Danube riverbed that was slowly removing the castle from the middle of the river. The main riverbed was shifted by the development of the bends to the Enghageni branch, south of the castle, and the 19th century river regulation preserved this situation, which was made worse by the construction of the hydroelectrical power plant between Abwinden and Asten, where the floodplain forest that was home to Spielberg Castle was located directly below the dam, and the drying out of the river had a major impact. The small tributaries forming the archipelago were filled up and the forest covering the different levels of geomorphology grew on the alluvium. To complete this process, Spielberg Castle was officially transferred administratively from Enns to Langenstein on the left bank on 1 January 1997. Spielberg Castle is still privately owned and a local NGO was established in 2013 to maintain and preserve it.

Spielberg castle as it seen today, south from the Gusen bridge (Google)

However, even if they succeed in restoring the castle, the Danube is unlikely to be diverted back to the lonely granite cliff, so the floodplain castle will not again become a unique hydrological curiosity; an island castle on the Danube. 

Translated with DeepL.com (free version)

The Rise and Fall of the Vienna Archipelago (1529-2010)

Cutting the Gordian Danube, Vienna 1875. (source)

IN HUNGARIAN

My absolute favourite book of 2023 was Wasser | Stadt | Wien. 458 pages of solid hydrology about Vienna, much of it of course about the Danube. The volume also includes nine full-page pictures of the changes in the river meanders around the city of Vienna. Lovers of urbanism will certainly find things of interest in the previously published images, but it is the floodplain patterns, which are now mainly similar to those of the Danube at Gemenc, Hungary, that are worth observing. It is a little known fact in Hungary that the Danube has caused far more serious problems in Vienna than in Budapest throughout the city's history. In historical times, the Danube flowed through a floodplain up to seven kilometres wide in Vienna, creating and destroying countless islands along this river section. The Viennese had an ambivalent relationship with the river, fearing its difficult crossing between the two banks and the many flood damages, but it was an advantage for the city in terms of trade. Around 1565, the main branch of the Danube moved away from the city and efforts by locals to bring the main shipping route back close to the city failed, leading to a compromise solution of extending the Vienna branch of the Danube, which later became the Donaukanal. 

Ugyanakkor a folyókanyarulatok vándorlása mellett a rendkívül fonatos meder gyakran okozott jégtorlaszokat. A budapestinél sokkal kevésbé stabilabb mederben a zátonyokon és szigetcsúcsokon kialakuló jégdugók gyakran eredményezték azt, hogy a télen levonult jeges árvíz kártételeinek felszámolása után a bécsiek már teljesen máshol találták meg a folyót. Ez az állandóan változó ártéri világ egyre inkább akadályává vált a város terjeszkedésének, amelyre megoldást kellett találni. Végül egy meglehetősen drasztikus beavatkozás szüntette meg a bécsi szigetvilágot 1870-1875 között, amikor is egy új, nyílegyenes medret ástak a Dunának, meghagyva egy széles, hasonlóan egyenes elöntési területet az árvizek számára. Az utóbbi időszak módosításai ezt a területet érintették, amikor a széles, kopár parti sáv helyén létrehozták a Donauinsel-t, melyet a bécsiek már sokkal inkább birtokba vehettek. 1875 után a lefűzött, kiszáradó folyókanyarulatok két utat jártak be. Ahol városi zöldfelületek területére estek, ott javarészt fennmaradtak (Prater, Alte Donau, Lobau, stb.), ahol viszont a város szövete ugrásra készen várta a kiszáradást, ott esetleg csak az utcák nyomvonala emlékeztet a régi medrekre (pl. Schwarze Lacke), többségük több méter feltöltés és beton alatt húzódnak. 

However, in addition to the migration of river meanders, the extremely braided riverbed was often clogged by iceblocks. In a much less stable bed than Budapest's, ice jams on sandbanks and islands often meant that, after the damage caused by the winter ice flood had been cleared up, the Viennese found the river in a completely different place. This ever-changing floodplain world became an increasing obstacle to the expansion of the city, and a solution had to be found. Eventually, a rather drastic intervention eliminated the Danubian archipelago in Vienna between 1870 and 1875, when a new, straight-edged bed was dredged for the Danube, leaving a wide, equally straight floodplain for the floods. More recent modifications to this wide, barren flood area included the creation of the Donauinsel, that was more easily occupied by the Viennese people. After 1875, the story of the newly created oxbows and drying river meanders took two paths. Where they fell into urban green spaces, they were largely preserved (Prater, Alte Donau, Lobau, etc.), but where the urban developers eager for more territory, only the street network may be reminiscent of the old riverbeds (e.g. Schwarze Lacke), most of them beneath several metres of landfill and concrete. 

Half a thousand years of river bend changes in Vienna 1529-2010 (source)

The nine detailed landscape reconstructions created using geographic information methods were almost begging for a .gif version. This version was most certainly created by the authors, but unfortunately the format is not compatible with the capabilities of the Guttenberg Galaxy. So I quickly put together my own version. In varying time-intervals, nine dates in total (1529, 1570, 1662-1683, 1704, 1780, 1825, 1875, 1912 and 2010), we can see the immediate surroundings of Vienna, with the Praterstern roughly in the centre.