It goes further back than that. Quoting from Ken's article: "In 1951, Maurice Wilkes came up with the idea of microcode: instead of building the control circu

It goes further back than that. Quoting from Ken's article: "In 1951, Maurice Wilkes came up with the idea of microcode: instead of building the control circuitry from complex logic gates, the control logic could be replaced with another layer of code (i. e. microcode) stored in a special memory called a control store. To execute a machine instruction, the computer internally executes several simpler micro-instructions, specified by the microcode. In other words, microcode forms another layer between the machine instructions and the hardware." Note the "1951".