Occurrence of Attributes in Original Text

The text related to the cultural heritage 'Persepolis' has mentioned 'Castle' in the following places:
Occurrence Sentence Text Source
The uneven plan of the terrace, including the foundation, acted like a castle, whose angled walls enabled its defenders to target any section of the external front.
From Stolze's investigations, it appears that at least one of these, the castle built by Xerxes I, bears traces of having been destroyed by fire.