Field marshal (or field-marshal, abbreviated as FM) is the second most senior military rank, ordinarily senior to the general officer ranks, but junior to the rank of Generalissimo. Usually, it is the highest rank in an army (in countries without the rank of Generalissimo), and as such, few persons are ever appointed to it. It is considered as a five-star rank (OF-10) in modern-day armed forces in many countries. Promotion to the rank of field marshal in many countries historically required extraordinary military achievement by a general (a wartime victory). However, the rank has also been used as a divisional command rank and also as a brigade command rank. Examples of the different uses of the rank include Afghanistan, Austria-Hungary, Pakistan, Prussia/Germany, India and Sri Lanka for an extraordinary achievement; Spain and Mexico for a divisional command (); and France, Portugal and Brazil for a brigade command (, ).
Provided by Wikipedia