Assertion: castle's curtain wall | /r/HasProperty | double
Facets:
Source sentences:
text: In German-speaking countries, many castles had double curtain walls with a narrow enclosure outside the main walls, acting as a killing ground between them, referred to as a zwinger.
text: In German-speaking countries, many castles had double curtain walls with a narrow ward between them, called a Zwinger (English lists, French lices).