Final answer:
The Medieval Period, also known as the Dark Ages, was considered so because of the lack of progress, limited written records, and the perception of decline during this time.
Step-by-step explanation:
The Medieval Period, also known as the Dark Ages, was once considered as such because of several reasons. Firstly, there was a lack of progress in terms of military strength, trade, and architecture during this time. Secondly, the limited surviving written records from this period led to a perception of a lack of intellectual and cultural development. Lastly, the term 'Dark Ages' was coined by Renaissance scholars who believed that the period between the fall of the Roman Empire and their own era was a time of darkness and decline.