Metric typographic units have been devised and proposed several times to overcome the various traditional point systems.
After the French Revolution of 1789 one popular proponent of a switch to metric was Didot, who had been able to standardise the continental European typographic measurement a few decades earlier.
The advent and success of desktop publishing (DTP) software and word processors for office use, coming mostly from the non-metric United States, side stepped this metrication process in typography.
[1] The German draft standard DIN 16507-2 has suggested that digital typography will be specified using millimeters, with sizes in multiples of 0.250 mm.
[1] German graphic designer and typographer Otl Aicher (1922 – 1991) vividly encouraged the use of the quart, and provided a suggested list of common sizes: Note that Aicher's font sizes are based on the DIN standard then in development, which uses the H-height, whereas in lead typesetting the larger cap height was used.