National Semiconductor PACE

National Semiconductor's IPC-16A PACE, short for "Processing and Control Element", was the first commercial single-chip 16-bit microprocessor, announced in late 1974. It was a single-chip implementation of their early 1973 five-chip IMP-16 architecture, which in turn had been inspired by the Data General Nova minicomputer.

Source: Wikipedia — National Semiconductor PACE (CC BY-SA 4.0)