What major world event caused Europe to enter a new era can
ter a new era called the Middle Ages

The Middle Ages, or medieval time, is generally believed to have started with the fall of the Roman Empire in 476 and to have lasted about 1,000 years until about 1450. The beginning of the Middle Ages is called the Dark Ages because the great civilizations of Rome and Greece had been conquered.

Explanation:

google gave me this, so i don't have an explanation.

im the bozz no matter what

d) he bring down boss tweed and tammany hall.