The 14th Century: The Black death

The economic boom of the 13th century was followed by the Black Death in the 14th century, a devastating plague all across the Silk Road. Europe lost 60% of its population; China's population decreased from 120 million to 80 million in a few years, and it took them about 4 centuries to take back their pre-Black Death population. The death, desperation, and fear was all over the Afro-Eurasian lands, and only  the inland Africa and the Americas which were far away from the Silk Road  remained intact.
Such a sudden shock weakened the Mongols, and this power vacuum gave rise to big empires in China (Ming), western Asia (Ottoman), and Europe (Christians). The common denominator between these rising powers were  keeping the dynasty inside the family and more importantly using religion and faith to rule over their subject people.