On Wed, 2009-04-15 at 19:08 -0700, Paul Kershaw wrote:

> A google for "question mark origin" turns up numerous sites that discuss "questio." In older fonts, the top half is more stylized. Also, in standard cursive, a capital Q more resembles a 2 than a print Q. The most established origin for ! is that it's from Io, a standard Roman exclamation of joy. Neither of these symbols are said to originate in the Roman Empire, but rather from a latter era in which Roman culture was romanticized.

Beware of the Internet, where anyone can air their theories! The 'Io"
story is on a par with the idea of deriving the English 's from "his".

In late Antiquity and the early Middle Ages, they used a system of dots:
on the line for a brief pause, mid-height for a colon, and high for a
period. The heights were probably difficult to distinguish as minuscules
replaced uncials and writing got smaller, and the dots were supplemented
by strokes above or below them (perhaps to show intonation), giving a
system used generally until the twelfth century, and in some monastic
orders until the end of the Middle Ages. This system included a question
mark, like the modern one but with a less pronounced curve and leaning
to the right. The system was largely lost in the later Middle Ages, when
a dash (virgula) or two often did duty for every pause.

The modern marks come from

period and comma: the virgula

colon: the early Medieval symbol

question mark: the early Medieval symbol

exclamation mark: invented in the fifteenth century by an Italian whose
name I've forgotten

semicolon: invented by Cardinal Pietro Bembo

quotation marks: developed from the "diple" (> or Ͻ) placed in the
margin alongside a Biblical quotation in ancient theologians, and
originally used in manuscripts of the classics to indicate a line
discussed in a commentary.

The standard work on the history of punctuation is M. B. Parkes: Pause
and effect (Scolar Press, 1992).