ISTANBUL’S LAND WALLS – TRANSFORMATION OF AN INTRA-URBAN GAP IN THE BUILT ENVIRONMENT)

For long periods of history, defensive fortifications of cities were not only absolutely necessary for the protection and prosperity of the community surrounded by the buildings, but due to the comparatively large extent of the fortifications and their persistence, they also remained determining factors of spatial development, morphology and functionality of urban centers for centuries. Only with the change in military paradigms (the emergence of effective, large caliber firearms) did these facilities prove to be outdated and obsolete, whereby several strategies could in principle be adopted for the subsequent use of the vacated areas: Either the building fabric was deliberately preserved and later integrated into the cityscape as cultural heritage (e.g. in Nördlingen, Basel or Lucca) or the walls were demolished and made way for wide boulevards with green spaces and high-quality building plots (e.g. Ringstraße in Vienna). In exceptional cases, such as in Istanbul, the city wall and its (terrestrial) apron remained "left over", so to speak, and was only put to modern use relatively late (about a thousand years after its construction). The spatial focus of the research presented in this paper lays on the urban space at and west of the land wall between the Eyüp district in the northern part of the Golden Horn and Zeytinburnu at the shoreline of the Marmara Sea and attempts to trace the transformation processes in the approximately 11.25 km² study area based on selected sources. The objects of consideration are functional as well as land use changes which took place within the last two centuries, whereby this restriction results from the special demands on the data material: In order to allow a quantitative assessment of the development, only qualitative appropriate plans, topographic maps and more modern digital GIS/RS data such as orthophotos and satellite images come into question. These sources are supplemented by material acquired during several field campaigns for data collection and verification in 2009, 2010 and 2011.