The Middle Ages as a time culturally dominated by religion, casting a shadow over the arts and sciences, preventing them from flourishing freely. This idea considered the Middle Ages to be the Dark Ages.
The word middle indicates something that is in an intermediate position. For the eighteenth-century thinkers known as the Enlightenment, this period of history was between Classical Antiquity, ended with the conquest of Rome by the Heruli in 476, and the Modern Age, of which they were a part, beginning with the conquest of city of Constantinople by the Ottoman Turks in 1453.
This was a way of looking at the world based on European history, disregarding the other regions of the planet. This kind of thinking was called Eurocentrism because it placed the European continent as the center of analysis. These eighteenth-century thinkers disregarded what had happened in other regions of the planet, such as the Islamic Empire, the Americas, or even China.
Moreover, during the Renaissance, it was conventionally called the Middle Ages of the Dark Ages because the Renaissance placed itself as heirs of thought and science developed by the Greeks and Romans, reviving the culture of antiquity. For the Renaissance, during the Middle Ages, the arts and sciences, compared to antiquity, had declined. The responsibility for this would be largely the Catholic Church, which dominated Europe politically, economically and culturally at the time. Religious domination would have impeded the development of reason, creating an era of backwardness and primitivism.