Question

Why do we have more information about medieval period than the ancient period?

Answer 1

Our information about the Modern period is also much more than that of the medieval period. In the most ancient period people were not much bothered about keeping record of events or of their activities. With the growth of civilisation, people became more conscious of recording events. With the development of language people now are more capable of recording events and conveying them to others. Availability of records is more in the case of middle ages than in the case of the ancient period as availability of records is more in the case of the modern period than in the case of the Middle ages. We have better methods of preserving records and better methods of disseminating them.
Between those two periods, there have been many invasions, revolutions, and changes in society.
Records have been lost and destroyed, by either man or natural processes.

That took me about 5 seconds to think of, why couldn't you have done that yourself.
medieval period was an era of darkness and back wardness in which very less development took place in the field of literature,art ,science etc.it was an era of church's hegemony and king had no control.

Answer 2

We have more information about the medieval period than the ancient period because, during the ancient period, people were not aware of the language in the result of that they were failed to keeping records and data.

While in the medieval period people become civilized and developed the Language due to which they were able to write record and incidents. The archaeologists and historians recovered written texts and manuscript which provide information about the medieval time.