to the thirteenth
century what Rome and Athens and the Italo-Hellenic influence generally had
{95} been to the ancient civilization. "If they did not possess the spirit
of invention which distinguished the Greeks and the Hindus, if they did not
show the perseverance in their observations that characterized the Chinese
astronomers, they at least possessed the virility of a new and victorious
people, with a desire to understand what others had accomplished, and a
taste which led them with equal ardor to the study of algebra and of
poetry, of philosophy and of language."[383]

It was in 622 A.D. that Mo[h.]ammed fled from Mecca, and within a century
from that time the crescent had replaced the cross in Christian Asia, in
Northern Africa, and in a goodly portion of Spain. The Arab empire was an
ellipse of learning with its foci at Bagdad and Cordova, and its rulers not
infrequently took pride in demanding intellectual rather than commercial
treasure as the result of conquest.[384]

It was under these influences, either pre-Mohammedan or later, that the
Hindu numerals found their way to the North. If they were known before
Mo[h.]ammed's time, the proof of this fact is now lost. This much, however,
is known, that in the eighth century they were taken to Bagdad. It was
early in that century that the Mohammedans obtained their first foothold in
northern India, thus foreshadowing an epoch of supremacy that endured with
varied fortunes until after the golden age of Akbar the Great (1542-1605)
and Shah Jehan. They also conquered Khorassan and Afghanistan, so that the
learning and the commercial customs of India at once found easy {96} access
to the newly-established schools and the bazaars of Mesopotamia and western
Asia. The particular paths of conquest and of commerce were either by way
of the Khyber Pass and through Kabul, Herat and Khorassan, or by sea
through the strait of Ormuz to Basra (Busra) at the head of the Persian
Gulf, and thence to Bagdad. As a matter of fact, one form of Arabic
numerals, the one now in use by the Arabs, is attributed to the influence
of Kabul, while the other, which eventually became our numerals, may very
likely have reached Arabia by the other route. It is in Bagdad,[385] D[=a]r
al-Sal[=a]m--"the Abode of Peace," that our special interest in the
introduction of the numerals centers. Built upon the ruins of an ancient
town by Al-Man[s.][=u]r[386] in the second half of the eighth century, it
lies i