Field Marshal was a military rank, ranking above general.
Thatcher was a UNIT field marshal stationed in Geneva in the 1960s or 1970s. (TV: The Invasion)
Erwin Rommel was a Nazi field marshal during World War II, (COMIC: The Instruments of War) as was Wilhelm Keitel. Keitel was responsible for signing the documents of Germany's surrender to the Soviet Union at the end of the war. (PROSE: Just War, AUDIO: Just War)