Why was the middle ages period once referred to as the "dark ages"

The Dark Ages is a term often used synonymously with the Middle Ages. It refers to the period of time between the fall of the Roman Empire and the beginning of the Italian Renaissance and the Age of Discovery. ... Debate continues to rage among historians over whether the Middle Ages were, indeed, dark or not.

zheng he was a chinese explorer who lead seven great voyages on behalf of the chinese emperor. his seven total voyages were diplomatic, military, and trading ventures, and lasted from 1405 – 1433. however, most historians agree their main purpose was to promote the glory of ming dynasty china.

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