Abraham Fraenkel grandpère writes on page 127 of his book recently translated into English:
My professional career began in March 1919 with... an invitation to Göttingen to Privy Counselor Felix Klein, almost 70 years of age, but still active as the "foreign minister" of German mathematics.
Is this to be interpreted as saying that Klein sought out Fraenkel's appointment at Göttingen?
Edit: As pointed out by @user37237, Klein actually invited Fraenkel to write an article on "number". I assume Fraenkel was already known at the time as a rising star in the new abstract field of axiomatic set theory. The fact that Klein asked Fraenkel to write an article on "number" seems to indicate that Klein still adhered to the importance of the arithmetisation of analysis, a term he coined in his 1895 Goettingen address.
Is it reasonable to assume that Klein invited Fraenkel to write an article on "number" because Klein considered set theory to be the foundation of such an arithmetisation?