Occurrence of Attributes in Original Text

The text related to the cultural heritage 'Castel del Monte' has mentioned 'Fortress' in the following places:
Occurrence Sentence Text Source
It has neither a moat nor a drawbridge and some considered it never to have been intended as a defensive fortress;[1] however, archaeological work has suggested that it originally had a curtain wall.
[1] The fortress is an octagonal prism with an octagonal tower at each corner.
Central to the plot of Umberto Eco's novel The Name of the Rose is an old fortress known as the 'Aedificium'.