Decade is part of Century. Century is related to Unit. Unit is related to Military. Military is related to Protocol. 
Mandate is a type of District. District is related to Part. Part is related to Rub. File entails/necessarily involves Rub. 
Decade --PartOf--> Century <--RelatedTo--> Unit <--RelatedTo--> Military <--RelatedTo--> Protocol 
Mandate --IsA--> District <--RelatedTo--> Part <--RelatedTo--> Rub <--Entails-- File 