Night of the Long Knives
The Night of the Long Knives (also known as Operation Hummingbird) occurred in National Socialist Germany between June 30 and July 2, 1934. At least eighty-five individuals were executed and more than a thousand arrested.
The politically correct view is that this was a National Socialist purge of the paramilitary SA organization which was seen as a possible threat, of internal NSDAP dissidents such as of the "left-wing" Strasserist faction, of homosexuals such as the SA leader Ernst Röhm, of external critics such as some conservatives, and to settle scores with old enemies. The purge strengthened and consolidated the support of the army leaders for Hitler.
A less politically correct view is that the evidence supports that Röhm and others were in fact (and as stated by Hitler) planning a coup (the Röhm Putsch with the German word "putsch" meaning "coup").
Before its execution, its planners sometimes referred to it as "Hummingbird" (German: Kolibri), as that was the codeword used to set the execution squads in motion on the day of the purge. The codename for the operation appears to have been chosen arbitrarily.
The phrase "Night of the Long Knives" in the German language predates the massacre itself. It is a reference to the massacre of Vortigern's men by Angle, Jute, and Saxon mercenaries in Arthurian myth. Until it became synonymous with the events of 1934, the phrase referred generally to acts of vengeance. Hitler argued that it in 1934 it was actually Röhm who first used the phrase as a name or codeword for his planned coup.