[mafribe]

Microcode is often attributed to [1] from 1952.

[1] M. V. Wilkes, J. B. Stringer, Micro-programming and the design of the control circuits in an electronic digital computer.

[kwhitefoot]

It's arguable that Babbage's design for the Analytical Engine included microcode.

See, i.a., https://www.fourmilab.ch/babbage/glossary.html

[mafribe]

Interesting, I had no idea. Wilkes doesn't cite Babbage, oh dear!