How and why do civilizations change over time?

What century was 899 ad? When was history.com created? What is a western tie called? Who controlled the city of Jerusalem when the crusades began their attack? What is the origin of the surname Schrewelius? How many rooms would a medieval cruck house have? What century was the year 1570? How was Roman Engineers Educated? What countries were under western influence after World War 2? What is the oldest city in the Midwest? What is the meaning of consummatum est? What was the Europeans perspective of First Nations? What symbol should be used to remember Canada's early European settlers? Is all quiet on the western front a true story? What is the highest selling CD in history? Why was spartacus considered a hero? What was Rome like at the height of the roman empire? What factors motivated europeans to participate in the crusades? What are characteristics of the roman republic? What civilization created the 365-day calendar?