[Sans a common enemy these 14th century thowbacks will always turn on each other.]
They have a common enemy - the non-Muslim world. But even Alexander needed to unite the Greeks before he ventured forth to conquer the world. Obviously he did not unite them by sitting around a campfire singing kumbaya. It involved bloody wars occasionally culminating in events like this:
https://en.m.wikipedia.org/wiki/Battle_of_Thebes#Alexander’s_march
[Alexander punished the Thebans severely for their rebellion. Wishing to send a message to the other Greek states, he had the 30,000 Thebans not killed in the fighting sold into slavery. The city itself was burnt to the ground, with the exception only of the house of Pindar, which Alexander ordered be left intact out of gratitude for Pindar’s verses praising Alexander’s ancestor, Alexander I of Macedon.[6]]
Would-be world conquerors have to start somewhere.