When did assigned seating come in ?

[WHBM]

I'm wondering when assigned seating was introduced generally in the industry (without fights about current operators who do/don't do it !). Back in prop aircraft days I get the impression it was not universal, and on some of the old multi-stop routes halfway around the world it would have been a nightmare to administer without telexing the complete seating plan from one station to the next as the flights progressed.