Similarly for central/eastern Europe the Mongol invasion in the 13th century was a major "dark age" setback: https://en.wikipedia.org/wiki/Mongol_invasion_of_Eu

Similarly for central/eastern Europe the Mongol invasion in the 13th century was a major "dark age" setback: https://en.wikipedia.org/wiki/Mongol_invasion_of_Europe https://en.wikipedia.org/wiki/Mongol_invasion_of_Europe