It took me roughly 5 seconds to go to Wikipedia, type "CP/M" into the search bar, scroll down to "History", where I found a link to an article about the Intel Intellec:
https://en.wikipedia.org/wiki/Intellec
The second sentence in that article says:
> The Intellec computers were among the first microcomputers ever sold, predating the Altair 8800 by at least two years.