9 Long-term Integrated Archaeological Prospection at the Roman Town of Carnuntum/Austria Wolfgang Neubauer, Michael Doneus, Immo Trinks, Geert Verhoeven, Alois Hinterleitner, Sirri Seren and Klaus Löcker Introduction Approximately 40 km south-east of Vienna on the southern bank of the Danube river, the site of the Roman military camp and civil town of Carnuntum constitutes the largest archaeological landscape in Austria (Jobst 1983; Vorbeck and Beckel 1973; Doneus et al. 2001), covering some 650 ha of archaeological area between the villages of Petronell- Carnuntum and Bad Deutsch Altenburg (Kandler 1994; 1997; 1998; Kandler et al. 2001a; 2001b). As the capital of the Roman province of Pannonia, Carnuntum was an important town during the first four centuries of the first millennium AD. So far only small parts of this archaeological site and the surrounding landscape have been investigated using traditional archaeological methods. Considerable archaeological excavation activity took place between 1877 and 1917, uncovering a larger number of structures at Carnuntum than at any period since (Jobst 1983). While in the nineteenth century Carnuntum still was named ‘Pompeii at the gates of Vienna’ due to the exceptionally good state of preservation of its ruins, this situation has changed drastically in the meantime. Intensive farming involving deep ploughing, infrastructure development, the construction of new housing estates in the nearby villages, and active looting by treasure hunters has caused a dramatic increase in the irreversible erosion of the archaeological stratification and destruction of this important cultural heritage site. In order to counteract this destructive development, both archaeologists and planners first need to know the exact location and extent of the threatened archaeological structures. While large-scale archaeological excavation and trenching has been used in the past for the investigation and reconstruction of the ancient city layout, modern archaeology increasingly makes use of non-invasive means for the exploration and mapping of the buried subsurface. In particular aerial archaeology and geophysical archaeological prospection methods have proven to be ideally suited survey methods of great value for the mapping and documentation of Roman city sites, as exemplified by the archaeological prospection of the ancient town of Carnuntum.