Alfred Pennyworth (somethimes know as Beagle) may have been created at the instigation of the producers of the first Batman movie serial.(Written by Victor McLeod, Leslie Swabacker, and Harry Fraser).  Or maybe not.  In any case, comic sidekicks were all the rage in 1943 when Alfred made his first appearance in Batman 16.

from "Here Comes Alfred" by Don Cameron, Bob Kane and Jerry Robinson  Batman 16 4/43

The serial came out in July 1943 and featured the tall skinny William Austin in the role of Alfred.  It took awhile for the comic books to adjust to the new look.

from "Accidentally on Purpose" Detective Comics 83 by Don Cameron, Bob Kane and Jerry Robinson, January 1944