Event is related to Ceremony. Ceremony is related to Master. Master is related to Professional. Technician is a type of Professional. 
Era is related to Modern. Modern is related to Technology. Technology is a type of Equipment. Equipment is related to Plate. 
Event <--RelatedTo--> Ceremony <--RelatedTo--> Master <--RelatedTo--> Professional <--IsA-- Technician 
Era <--RelatedTo--> Modern <--RelatedTo--> Technology --IsA--> Equipment <--RelatedTo--> Plate 