So you've got an earlier citation for either 1) someone using positional notation with digits for 1 and 0 and performing base 2 arithmetic on them or 2) some

So you've got an earlier citation for either 1) someone using positional notation with digits for 1 and 0 and performing base 2 arithmetic on them or 2) someone using positional notation in arbitrary bases, and generally establishing that that would work for any base down to and including 2 ? People had to realize that that worked. It's not obvious; it's not obvious that just because decimal and duodecimal work to count to every number that the same is true for any base; it's not obvious that it will continue working for base 2, where you can only count up to 1, which seems like it might be underpowered for the task. "Of course it works for 2!" you cry? Well, it doesn't work for 1.