<http://caligraph.org/ontology/Dark_age>	<http://www.w3.org/2000/01/rdf-schema#subClassOf>	<http://caligraph.org/ontology/Historical_era> .
<http://caligraph.org/ontology/Middle_Age>	<http://www.w3.org/2000/01/rdf-schema#subClassOf>	<http://caligraph.org/ontology/Historical_era> .
<http://caligraph.org/ontology/Ice_age>	<http://www.w3.org/2000/01/rdf-schema#subClassOf>	<http://caligraph.org/ontology/Historical_era> .
<http://caligraph.org/ontology/Classical_music_era>	<http://www.w3.org/2000/01/rdf-schema#subClassOf>	<http://caligraph.org/ontology/Historical_era> .
<http://caligraph.org/ontology/Japanese_era>	<http://www.w3.org/2000/01/rdf-schema#subClassOf>	<http://caligraph.org/ontology/Historical_era> .
<http://caligraph.org/ontology/Historical_era>	<http://www.w3.org/ns/prov#wasDerivedFrom>	<http://en.wikipedia.org/wiki/Category:Historical_eras> .
<http://caligraph.org/ontology/Golden_age_(metaphor)>	<http://www.w3.org/2000/01/rdf-schema#subClassOf>	<http://caligraph.org/ontology/Historical_era> .
<http://caligraph.org/ontology/Historical_era>	<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>	<http://www.w3.org/2002/07/owl#Class> .
<http://caligraph.org/ontology/Works_about_historical_era>	<http://www.w3.org/2000/01/rdf-schema#subClassOf>	<http://caligraph.org/ontology/Historical_era> .
<http://caligraph.org/ontology/Calendar_era>	<http://www.w3.org/2000/01/rdf-schema#subClassOf>	<http://caligraph.org/ontology/Historical_era> .
<http://caligraph.org/ontology/Historical_era>	<http://www.w3.org/2000/01/rdf-schema#label>	"Historical era" .
<http://caligraph.org/ontology/Era_of_United_States_history>	<http://www.w3.org/2000/01/rdf-schema#subClassOf>	<http://caligraph.org/ontology/Historical_era> .
<http://caligraph.org/ontology/Historical_era>	<http://www.w3.org/2000/01/rdf-schema#subClassOf>	<http://www.w3.org/2002/07/owl#Thing> .