What was the Concert of Europe designed to do?

What year did the Gregorian calendar begin? Describe the crusades and why they occured? What does century mean? What does C.E. mean on the timeline? Where were the most important towns in the 11th century? What is the difference between the states formed by the First Civilizations and the empires formed between 500 BC and 500 CE? Why do historians sometimes refer to the monarchies of the late fifteenth century as new monarchies or Renaissance states? What was the bread and circuses policy and how did Romans politicians benefit from it? Who owned the first clock in history? How long has DRYWALL been in existence? What years did Marcus junius Brutus rule? How did the early Western world react to the lack of centralized government? Is Charles Martel and Charlemagne the same person? Why did the christian europeans win the first crusade? What is the menistis? Causes and effects of the crusades? In which century did the crusades take place? What century and what millennium is 2020? What is the duration of Middle Age Spread? What does the term Inherit the Wind comes from?