For some time now, blitz (in any of various formats) has been a very popular format of chess.
It is obvious that in order to play blitz you need to have a chess clock and these have been around for about 150 years.
When did people start playing blitz games? It was right after chess clock were introduced or the habit took a long time to catch?
In particular, does anyone know when is the earliest reference of blitz? Not talking about the game's score or even the players' names, but just the earliest mention of games played at a fast time control.