Thebes, 350 miles towards the south in Upper Egypt, tried to make itself
master of the entire valley. In the year 2400 B.C. they succeeded. As
rulers of both Upper and Lower Egypt, they set forth to conquer the rest
of the world. They marched towards the sources of the Nile (which they
never reached) and conquered black Ethiopia. Next they crossed the
desert of Sinai and invaded Syria where they made their name feared by
the Babylonians and Assyrians. The possession of these outlying
districts assured the safety of Egypt and they could set to work to turn
the valley into a happy home, for as many of the people as could find
room there. They built many new dikes and dams and a vast reservoir in
the desert which they filled with water from the Nile to be kept and
used in case of a prolonged drought. They encouraged people to devote
themselves to the study of mathematics and astronomy so that they might
determine the time when the floods of the Nile were to be expected.
Since for this purpose it was necessary to have a handy method by which
time could be measured, they established the year of 365 days, which
they divided into twelve months.

Contrary to the old tradition which made the Egyptians keep away from
all things foreign, they allowed the exchange of Egyptian merchandise
for goods which had been carried to their harbors from elsewhere.

They traded with the Greeks of Crete and with the Arabs of western Asia
and they got spices from the Indies and they imported gold and silk
from China.

But all human institutions are subject to certain definite laws of
progress and decline and a State or a dynasty is no exception. After
four hundred years of prosperity, these mighty kings showed signs of
growing tired. Rather than ride a camel at the head of their army, the