Assertion: fortress's wall | /r/HasProperty | protected against the sea
Facets:
Source sentences:
text: The wall's proximity to the sea and the strong currents of the Propontis meant that eastern and southern shores of the peninsula were comparatively safe from attack, but conversely, the walls had to be protected against the sea itself: a breakwater of boulders was placed in front of their base, and marble shafts were used as bonds in the walls' base to enhance their structural integrity.