Assertion: black truffle | /r/HasProperty | breakthrough
Facets:
value: in truffle cultivation
type: LOCATION
value: in the early 19th century
type: TEMPORAL
Source sentences:
text: Périgord black truffles were collected in the wild in France from at least the Middle Ages onwards, but it was a breakthrough in truffle cultivation in the early 19th century that transformed a peasant pastime into big business.