2. The destruction of a highly developed civilization as a result of some catastrophe. An example is Mohenjo-Daro; probably not the only example. And even if scientific knowledge is preserved for posterity, but they are not developed enough to use it – it can die purely by accident. Thus, in Byzantium, all ancient scientific and artistic texts were brought to the library in Constantinople. This centralization destroyed them: the library burned down in 1203 during the assault of Constantinople by the Crusaders. This would not have happened if literary monuments were not just in the library, but were read and used in the deed; then they would have been copied.