Nine is correct, AFAIK.
The Marshall Marshall thing is a good story
, but I think the more operative one is that there was a deliberate intent not to have Gen. Pershing outranked while he was still alive, thus the distinction between General of the Armies and General of the Army.
I always found it interesting that a FIELD Marshall (by defintion) earned that rank by either leading a successful campaign or by besieging and taking a defended fortress. Did any of our five-star officers earn their fifth star as a result of field operations? I can't think of any who did, but I do not recall when the Admirals received their promotions.
Eisenhower, for example, received his fifth star shortly before the Battle of the Bulge, and thus was hardly "commanding, in the field." He subsequently neary entirely turned over tactical control of the Bulge operation to Patton, to whom he even joked that every time he (Eisenhower) got another star, he got attacked! Bradley received his fifth star long after he had left the European Theatre, and thus the rank was purely honorary, rather than a matter of necessity of command, was it not? (Even as Chief of Staff, had he had the five-star rank, he still would not have out-ranked MacArthur.)
Anyone able to shed any light on this?
General Arnold was a General of the Army. The Air Force and Marines have never had a five-star officer.