Possibly the oldest hand cannon dated 1346

[fernando]

It should perhaps be said that there have been two Roman numeral tables, one in more archaic early times and a so called modern one; notwithstanding that one used by illiterate peoples, where figurative symbols were used.
The early one had an 'addictive' principle whereas in the later a 'subtractive' principle took place, were symbols added to a point and then subtracted.
Like so:

.