148 EARLY MEDIEVAL SPAINconcerning the spread of Islam and of the Arabs need to be consid-
ered here. Some major issues, such as the underlying causes of the
success of the conquests that covered such an enormous extent of
territory and were achieved so rapidly, remain controversial and the
explanations advanced have to retain the character of co~ecture. It
is unlikely that a single answer will fit all cases, in view of the diver-
gences of society, culture and geography encompassed in the area of
the conquests.lO An approach from the point of the conquerors is
more likely to prove fruitful. One obvious problem is that of man-
power. As the Arabian peninsula was clearly not depopulated in the
process, what were the human resources employed in these remark-
able expansions, achieved by the hardly numerous inhabitants of one
of the world's most desolate regions?
A related question is that of how Islamicised the Arab tribes were
by the time of the death of Mui).ammad and the sudden military
expansion that followed. By traditional chronology eight years out of
the last decade of the Prophet'S life were spent in making him master
of the Hijaz, the region of central western Arabia in which Mecca
and Medina were the chief settlements. Although this process must
have affected most of the tribes in that area, it only leaves two years
(630-632) for Islam and the authoritY of Mecca to be imposed upon
the rest of the peninsula, including Persian-rulpd Yemen. Islamic
sources which imply that this happened are reticent as to the means
of its achievement. Even allowing that the essential tenets of Islamic
belief and practice had become firmly established during the Proph-
et's lifetime, a notion which has not gone unchallenged, and which
the history of most of the world's other great religions might lead
one to doubt, its hold over its first recipients was still very new, even
at the time of their conquest of Spain. Furthermore, that they were
relatively few in number in comparison with the populations of the
areas of their new empire makes the subsequent spread of the Arabs
in those regions all the more remarkable.
However, the first phase of the Arab conquests, in the 630s, had
taken place in regions such as Syria, Palestine and southern Mesopo-
tamia, in which a predominately Arab or Semitic population lived in
both town and countryside. Absorption of elements of these cultur-
ally and linguistically related populations into the society of the con-
querors was relatively easy, and quickly enhanced their military
potential. This was achieved not least through the processes of en-
slavement and manumission. Non-Muslims captured in war were