while
somewhat vaguer records give us glimpses of periods as remote as the
sixth, perhaps even the seventh or eighth millenniums before our era.

At a very early period Babylon itself was not a capital and Nineveh
had not come into existence. The important cities, such as Nippur and
Shirpurla, were situated farther to the south. It is on the site of
these cities that the recent excavations have been made, such as those
of the University of Pennsylvania expeditions at Nippur,(6) which are
giving us glimpses into remoter recesses of the historical period.

Even if we disregard the more problematical early dates, we are
still concerned with the records of a civilization extending unbroken
throughout a period of about four thousand years; the actual period is
in all probability twice or thrice that. Naturally enough, the current
of history is not an unbroken stream throughout this long epoch.
It appears that at least two utterly different ethnic elements are
involved. A preponderance of evidence seems to show that the earliest
civilized inhabitants of Mesopotamia were not Semitic, but an alien
race, which is now commonly spoken of as Sumerian. This people, of whom
we catch glimpses chiefly through the records of its successors, appears
to have been subjugated or overthrown by Semitic invaders, who, coming
perhaps from Arabia (their origin is in dispute), took possession of the
region of the Tigris and Euphrates, learned from the Sumerians many of
the useful arts, and, partly perhaps because of their mixed lineage,
were enabled to develop the most wonderful civilization of antiquity.
Could we analyze the details of this civilization from its earliest to
its latest period we should of course find the same changes which always
attend racial progress and decay. We should then be able, no doubt,
to speak of certain golden epochs and their periods of decline. To a
certain meagre extent we are able to do this now. We know, for example,
that King Khammurabi, who lived about 2200 B.C., was a great law-giver,
the ancient prototype of Justinian; and the epochs of such Assyrian
kings as Sargon II., Asshurnazirpal, Sennacherib, and Asshurbanapal
stand out with much distinctness. Yet, as a whole, the record does not
enable us to trace with clearness the progress of scientific thought.
At best we can gain fewer glimpses in this direction than in almost
any other, for it is the record of war and conquest rather than of the
peaceful arts