The earlier years of the middle ages began with
a. the crusades.
b. the collapse of the roman empire.
c. the renaissance.
d. the search for new trade routes.

The earlier years of the Middle Ages began with the collapse of the Roman Empire - b.

The Middle Ages are characterized with the sacking of Rome at the end of the fifth century. This brought upon the downfall of the (western) roman empire and with that also marked the beginning and the early years of the Middle Ages. 

They said that the world was flat