Occurrence of Attributes in Original Text

The text related to the cultural heritage 'Palace of Westminster and Westminster Abbey including Saint Margaret’s Church' has mentioned 'Castle' in the following places:
Occurrence Sentence Text Source
The architect conceived the great square tower as the keep of a legislative "castle" (echoing his selection of the portcullis as his identifying mark in the planning competition), and used it as the royal entrance to the Palace and as a fireproof repository for the archives of Parliament.