John J. Pershing actually held the rank of “General of the Armies”, the same rank that Gen. Washington was elevated to in 1976. When the 5-star ranks (Gen. of the Army / Fleet Admiral) were created for WW2 they were considered to be one grade below. IOWs, Pershing & Washington are in effect 6-star generals. Note: No insignia were ever developed. Pershing never wore more than 4 stars in any picture that I ever saw.
General of the Armies of the United States is a distinct rank above the ranks of General of the Armies and General of the Army. It was created to insure that George Washington will always outrank Grant, Sherman, Pershing, MacArthur, Eisenhower, Marshall, Arnold and Bradley and all other officers of the US Army.