Question mark
In the early 13th century, when the growth of communities of scholars (universities) in Paris and other major cities led to an expansion and streamlining of the book-production trade, punctuation was rationalized by assigning Alcuin's stroke-over-dot specifically to interrogatives; by this time the stroke was more sharply curved and can easily be recognized as the modern question mark.
Question mark
It has also been suggested that the glyph derives from the Latin "quaestiō" meaning "question", which was abbreviated during the Middle Ages to "qo". The lowercase "q" was written above the lowercase "o", and this mark was transformed into the modern symbol. However, evidence of the actual use of the Q-over-o notation in medieval manuscripts is lacking; if anything, medieval forms of the upper component seem to be evolving towards the q-shape rather than away from it.