What were challenges for Islamic Caliphates in ruling such a large imperial territory?

What solutions were tried?

What were challenges for Islamic Caliphates in ruling such a large imperial territory?
What they did was a sort of federal regime. they divided the place into many emirates and on each one a prince. While the Califa was managing everything from his main position in Arabia, Damascus, or Baghdad according to the era. But this regime had many inconveniences: It reduced the authorities of the Califa, it encouraged each prince to reclame an independent territory and that produced the destruction of this empire.
Reply:Ruling of such a large imperial territory was a tough job. They had made many such ways of ruling this empire by giving or donating bigger lands to their people. People such as their trustworthy bodyguards etc.. which their decendents till now ruling.