Assertion: castle's fortification | /r/CapableOf | prove difficult to overcome
Facets:
value: for the invading force
type: TRANSITIVE-OBJECT
value: quite
type: DEGREE
Source sentences:
text: For the invading force, these fortifications proved quite difficult to overcome, and accordingly, fortresses occupied a key position in warfare.
text: For the invading force, these fortifications proved difficult to overcome.