The came right before the middle ages

The Early Middle Ages or Early Medieval Period came right before the Middle Ages.

The Early Middle ages, Early Medieval Period, or even, Late Antiquity, points to a period of time typically referred as lasting from the 5th or 6th century to the 10th century CE. They mark the start of the Middle Ages in European history, and when Late Antiquity is referenced, it is done to accentuate the elements of continuity between the Roman Empire and the transition to the medieval period.  

wheres the following authors?

the answer would either be a or d

i hope this