Historical studies show that people have been thinking about protection and defence ever since they first started building settlements; that is, from first human encroachment into the environment (in prehistory), when they stopped looking for natural shelters instinctively and consciously started building and living in them. It is not difficult to see that throughout historical development in space human self‑protection has always been expressed in various ways. In fact, this has to do with various measures that people used to protect themselves from wars and in this article they are referred to as strategic urban defence. Above all, this depended on natural conditions (location) but also on the strategic resourcefulness and imagination of individuals in the urban and architectural sense as well as on weapons and other means that were constantly altered throughout history and from war to war. In human historical development there were always people that had an innate talent for warfare (Alexander the Great, Attila and others) as well as for collective self‑protection; that is, strategic urban defence. The case of Ljubljana shows that by the Middle Ages there were military experts in architecture and construction that were in charge of ensuring greater effectiveness in implementing strategic urban defence. Until very recently, similar experts in strategic urban defence were in charge of constructing public fallout shelters. A historical, archaeological, geographic, urban and architectural overview of the modern Ljubljana area showed that here as well principles of strategic urban defence have been used continually from prehistory until today. However, because they have not been sufficiently studied in the existing literature on urbanism and architecture of Ljubljana, all important findings in this research relating to strategy in a larger area had to be analysed and compared and then new conclusions had to be drawn based on new findings. The most important question was whether Ljubljana’s first settlement core (Old Square) was established by coincidence. The analysis clearly showed that the settlement was established at this location originally as a farming and military settlement and that