Which philosopher was the founder of zoology, as well as had advances in meteorology, politics, ethics, and psychology?

In Ancient Egypt, tomb walls were left blank as paintings were considered bad luck in the afterlife.

The Crusades was fighting between

The Romans had a time of peace, which was not very peaceful.  But it was a time when the average Roman citizen did not have to worry about an outside invasion.  What was this time called?

What caused trade to take place?

The Black Death was brought to Europe by the Silk Road.

 The lack of government in trade and business is called

What was the main goal of the Crusades?

The Yellow River Valley civilization had a belief that there is a guiding force in the universe that will throw out immoral leaders.  This was known as the

The Enlightenment is also called the Age of Reason.