The term 'sphere of control' is a concept used in political science and sociology to refer to the area of influence or authority that an individual or group has over a certain domain. The term 'FIEF' is a synonym for this concept, and is derived from the medieval feudal system, where a lord would grant a fiefdom to a vassal in exchange for loyalty and service. In modern terms, a FIEF is a domain or area of influence that is granted to an individual or group by a higher authority.