"Show me just what Mohammed brought that was new, and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached." - Manuel II Palelologus
If Italy is divided or partitioned, within 40 years most of the “South” however defined will see the native Italian population become the minority in their own homelands.
With that foothold, Arabisation of the Mediterranean can increase much more rapidly as they take control of “south Italy’s” political and economic reins of power.