The actor model is from 1974, Erlang from 1986.
I can’t remember if we knew about the actor model in 1985 I might have heard of it without knowing what it was. Erlang was directly influenced by smalltalk and prolog.
The idea of messaging comes from smalltalk and CSP. There are sufficient similarities between Hewitt’s actors and Erlang so I guess you can call Erlang an actor language - but Erlang has many things not in actors (like links etc.)
