Occurrence of Attributes in Original Text

The text related to the cultural heritage 'Acropolis, Athens' has mentioned 'Fortification' in the following places:
Occurrence Sentence Text Source
Homer is assumed to refer to this fortification when he mentions the "strong-built House of Erechtheus" (Odyssey 7.81).
Strong fortification walls have surrounded the summit of the Acropolis for more than 3,300 years.
The first fortification wall was built during the 13th century BC, and surrounded the residence of the local Mycenaean ruler.
Firstly, it was the Mycenaean Acropolis (Late Helladic civilization, 1600-1100 BC) which included the royal residence and was protected by the characteristic Mycenaean fortification.