It has repeatedly been made a question--at what era we are to date the
transition from ancient to modern history. This question merits a
separate dissertation. Meantime it is sufficient to say in this
place--that Justinian in the 6th century will unanimously be referred
to the ancient division, Charlemagne in the 8th to the modern. These
then are two limits fixed in each direction; and somewhere between
them must lie the frontier line. Now the era of Mahomet in the 7th
century is evidently the exact and perfect line of demarcation; not
only as pretty nearly bisecting the debatable ground, but also because
the rise of the Mohammedan power, as operating so powerfully upon the
Christian kingdoms of the south, and through them upon the whole of
Christendom, at that time beginning to mould themselves and to knit,
marks in the most eminent sense the birth of a new era.