Darwin Core term name: relationshipEstablishedDate. The date-time on which the relationship between the two resources was established. Recommended best practice is to use an encoding scheme, such as ISO 8601:2004(E). This property is currently not used.

public string RelationshipEstablishedDate { get; set; }

Public Property RelationshipEstablishedDate As String
	Get
	Set

public:
property String^ RelationshipEstablishedDate {
	String^ get ();
	void set (String^ value);
}

member RelationshipEstablishedDate : string with get, set