When Did The 'Heil Hitler' Greeting Start?

 This is an interest history story.

So the earliest use of 'Sieg Heil' or 'Heil Hitler' was in 1921....within the small but growing Nazi Party out of Munich.  The bulk of the early members were veterans of WW I.

So as you get to 1926....it became an official use thing by party members.

Later, as you get into the late 1930s....the 'greeting' became mandatory for civilians.

My wife (the German) has the letter from the commander of her grandfather's unit....from the 1st week of January 1945...noting the passing of her grandfather in defending some roadway at the far end of eastern Poland....as the Army were exiting Russia.

The letter ends with 'Heil Hitler' and the guy's signature.  I would imagine about a month after the event, the guy's wife got the letter.