The Mongols devastated the eastern lands of Islam and ruled from the Sinai Desert to India for a century. But they soon converted to Islam and became known as the Il-Khanids. They were in turn succeeded by Timur and his descendents who made Samarqand their capital and ruled from 1369 to 1500. The sudden rise of Timur delayed the formation and expansion of the Ottoman empire but soon the Ottomans became the dominant power in the Islamic world.
"When a person dies, his works end, except for three: ongoing charity, knowledge that is benefited from, and a righteous child who prays for him."
Prophet Mohammed (PBUH)
"The best of what a man leaves behind are three: a righteous child who supplicates for him, ongoing charity the reward of which reaches him, and knowledge that is acted upon after him."
Sunan Ibn Mājah
"Every day two angels come down from Heaven and one of them says, 'O Allah! Compensate every person who spends in Your Cause,' and the other (angel) says, 'O Allah! Destroy every miser.'"
Sahih Bukhari