"Among Tiro’s notae was an innocuous character representing the Latin word et, or “and.” Though this was only one symbol among many (in their most elaborate medieval form, a system descended from Tiro’s original cipher comprised some fourteen thousand glyphs), the utility of Tiro’s system ensured that his et sign would considerably outlive both its creator and its sponsor. This was not, however, the storied ampersand: when Tiro created his so-called Tironian et, the ampersand was still more than a century away."

The book itself is worth a read for all the other punctuation marks it discusses.