Assertion: postage stamp | /r/HasProperty | the penny black
Facets:
value: commonly
type: DEGREE
Source sentences:
text: The first stamp, the "Penny black", became available for purchase 1 May 1840, to be valid as of 6 May 1840.
text: The first adhesive postage stamp, commonly referred to as the Penny Black, was issued in the United Kingdom in 1840.