long knives

I've been asked about the origin of the name, or codename, of the well known "Night of Long Knives"_
I'm not able to answer_ someone could enlighten me, or could indicate some useful link about that ?_
as ever, thank you very much !

Computer translation from a German website:

The massacre of the British (Celtic) aristocrats by the anglo-saxon immigrants in the year 450 in Salisbury which was described, among others, by the medieval British historian Geoffrey of Monmouth. Therefore, the request on the murder occurred through the call: "Nemet oure Saxas". In Welsh this event was called Brad y Cyllyll Hirion („The betrayal of the long knives“).

The murder series in 1934 by order of Hitler in which all potential competitors Hitler (from Schleicher, Röhm, Gregor Strasser) became murdered or neutralised (from Papen) was shown by Goebbels propagandistic as a Röhm-Putsch. In particular the whole guidance SA was murdered on order Adolf Hitler. In Germany this event is meant with „night of the long knives“ mostly.

Some sources mention the code word "Kolibri" (hummingbird) was used for the order to murder the SA leaders.

Amberg,
thank you very much !
I would never suppose this kind of origin_ by the way, I'm quite astonished that isn't coming from some ancient German heritage_
Anyway, sincerely thanks for your interest and your help_
(this question was more difficult than obtain a picture of the gas-burner painted on some of the Peiper's vehicles during the war in Russia!)