Assertion: castle's location | /r/HasProperty | built on dolerite
Facets:
Source sentences:
text: Built on a dolerite outcrop, the location was previously home to a fort of the indigenous Celtic Britons known as Din Guarie and may have been the capital of the kingdom of Bernicia, the realm of the Gododdin people, from the realm's foundation in c. 420 until 547, the year of the first written reference to the castle.