Why is the period between 600-1450 ce referred to as the dark ages? were they "dark" globally? if not, give examples?

Between the time periods of 600-1450 Common Era, it was referred to as the dark ages in Europe because the cities and regions in Europe lack poetry, which was a dark experience. It was not really a dark globally, but only in the part of Europe wherein poetry vanished, but right after the dark ages, was the beginning of the modern age, which gave life to poetry and to music once more.