What was the Mac that Ran 'System 1'

I thought I was reasonably early to the party, but the first Mac I owned - an SE 30 - was running System 6.06 when I got it & after a brief foray with 6.06 we had 6.07 with actual multi-tasking…

…but what machine ran System 1?
…& was it even called that at the time?

Solution 1:

According to EVERYMAC, the Macintosh Original (128k), 512k, and 512ke (ED) were the only versions that were shipped with System 1.

Solution 2:

Wikipedia to the rescue, they even have an article dedicated to System 1:

System 1, also known as Macintosh System Software was the original Macintosh operating system. It is a part of the Classic Mac OS family, and ran on the Motorola 68000 microprocessor. It was released on January 24, 1984 along with the original Macintosh and was replaced by System 1.1 on May 5, 1984.

and a lot more about all other releases.