Reading through Second World War literature, one finds confirmation that the higher ranking Allied commanders were "privy to the Ultra secret" or words to that effect. This seems to include Army-level commanders like Patton and Simpson as well as Eisenhower and Montgomery. But how much did they really know? Eisenhower seems to have been briefed all about Bletchley Park, but did the army commanders know anything about Ultra beyond that the information was the result of British breaking of the Enigma transmissions?