“Prior to 1737, little standardisation existed in the sizes of printing types and typefounders cast types to their own sizes and dimensions. In this year, the Parisian typefounder Pierre Simon Fournier introduced a new system that he derived from dividing two inches of the pre-metric French foot into one hundred and forty-four equal parts. Fournier gave the resulting unit a name – ‘points’ – and they measured 0.137 of the English inch, which is close to the present point system…”
Read the rest here. I love that the term Nonpareil is equivalent to 6 points.