contained, at the time of its invasion
by the Vandals under Genseric, in the year 430 of the Christian era,
twenty millions of inhabitants, and had come to be regarded with reason
as the garden of the human race. "The long and narrow tract," says
Gibbon, "of the African coast was filled, when the Vandals approached
its shores, with frequent monuments of Roman art and magnificence; and
the respective degrees of improvement might be accurately measured by
the distance from Carthage and the Mediterranean. A simple reflection
will impress every thinking mind with the clearest idea of its fertility
and cultivation. The country was extremely populous; the inhabitants
reserved a liberal supply for their own use; _and the annual
exportation_, PARTICULARLY OF WHEAT, _was so regular and plentiful, that
Africa deserved the name of the common granary of Rome and of
mankind_."[43] Nor had Spain flourished less during the long
tranquillity and protection of the legions. In the year 409 after
Christ, when it was first invaded by the barbarians, its situation is
thus described by the great historian of the _Decline and Fall of the
Roman Empire_. "The situation of Spain, separated on all sides from the
enemies of Rome by the sea, by the mountains, and by intermediate
provinces, had secured the long tranquillity of that remote and
sequestered country; and we may observe, as a sure symptom of _domestic
happiness_, that in a period of 400 years, Spain furnished very few
materials to the history of the Roman empire. The cities of Merida,
Cordova, Seville, and Tarragona, were numbered with the most illustrious
of the Roman world. The various plenty of the animal, _vegetable_, and
mineral kingdoms was improved and manufactured by the skill of an
industrious people, and the peculiar advantages of naval stores
contributed to support an extensive and profitable trade." And he adds,
in a note, many particulars relative to the _fertility_ and trade of
Spain, may be found in Huet's _Commerce des Anciens_, c. 40, p. 228.[44]

These facts are very remarkable, and worthy of the most profound
attention; for they point in a decisive manner, they afford the
_experimentum crucis_ as to the real cause of the long-continued and
frightful decay of Italian agriculture during the reign of the emperors.
For here, it appears, that during the four hundred years that the
Western Empire endured, while the cultivation of grain in Italy was
constantly declining, and