The period of time from the fall of Rome around 600 CE to the Renaissance around 1450 CE is called the middle ages, and sometimes referred to as the dark ages, but this is a misnomer. The dark ages were not very dark at all, especially if you weren’t in Europe.
During this time period, Europe had less trade, fewer cities, and less cultural output than the previous roman empire. Since there weren’t many powerful governments, wars were smaller.
Feudalism was the economic system of the times, with local lords ruling over a chunk of land, and peasants working on that land and giving much of the output to the lord. There was no social mobility for peasants in this society, but their life expectancy was slightly higher than during the roman empire, possibly because of the lack of big wars.
Meanwhile outside of Europe, the Abbasid empire fostered an openness to foreigners and ideas, and ushered in a golden age of Islamic learning centered in Baghdad. Arabic replaced Greek as the language of commerce, religion, and culture. Islamic people translated Aristotle, Plato, Archimedes and many more.
They made huge strides in medicine, creating what would become the standard medical textbook for centuries. They also made great advances in mathematics, agricultural science, and other subjects.
The chinese kingdom at this point consisted of over 80 million people over 4 million square miles. They might have conquered all of central Asia if it wasn’t for the Abbasids. The Chinese made incredible art that was traded all throughout Asia. This was also a golden age for Chinese poetry.
11th century Chinese metal workers produced as much iron as Europe was able to produce in the 18th century. With a boom in agriculture they were able to support their growing population.
Chinese Porcelain was so highly traded and known throughout the world that people called it “china”. They were doing so much trade that they ran out of metal for coins, leading to the creation of paper money.
It was also during this time period that they invented gunpowder, which turned out to be a very impactful invention.