Occurrence of Attributes in Original Text

The text related to the cultural heritage 'Persepolis' has mentioned 'Fortification' in the following places:
Occurrence Sentence Text Source
[17] According to archaeological evidence, the partial burning of Persepolis did not affect what are now referred to as the Persepolis Fortification Archive tablets, but rather may have caused the eventual collapse of the upper part of the northern fortification wall that preserved the tablets until their recovery by the Oriental Institute's archaeologists.