Assertion: leap year's day | /r/HasProperty | multiples of 4
Facets:
Source sentences:
text: From AD 8 the Julian calendar received an extra day added to February in years that are multiples of 4.
text: From AD 8 the Julian calendar received an extra day added to February in years that are multiples of 4 (although the AD year numbering system was not introduced until AD 525).