What’s the story behind Times New Roman Medium? How recent is this addition to the TNR family? What was its purpose?

It is a well-known fact that Times Semi-Bold (Series 421) was developed by Monotype Corporation in 7-pt. size, at the request of CUP, for a Cambridge edition of the Bible; the year was 1936.

The Medium’s design copyright is dated 1988. There is a lot more recent Times New Roman cut, Seven, optically optimised but different in design from both the Semi-Bold and the Medium; its glyph shapes are more faithful to the letter-forms of the original Times New Roman (Series 327) than Semi-Bold’s. The Seven’s design copyright is dated 1988 too… There was also Series 610, cut in 6½ size in 1959 ‘for the exclusive use of the Oxford University Press’ but that’s another story in its entirety.