How did the wealth the Abbasids gain also lead to their downfall?
By that time, because the Abbasids had such a strong Islamic caliphate, Baghdad was its capital, ruled by caliph heron-al Rashid, Baghdad was also an important place as a trade center, so it was filled with magnificent buildings and gardens, people, merchants etc. came to sell goods, learn their language the Arabic, and many had been exposed to Islam, naturally helping Islam to spread widely, people from conquered lands such as Egypt just had to learn Arabic. However, with the fall of the Abbasids, mainly because each leader had become more and more independent, along with the Mongols attacking, the empire had lost control with power, erasing all of above of achievements, and so Islam didn’t have what it had before to flourish.
