Sometimes it seems that my genocidal spreading of christianity and Greekness into Africa and the Middle East might have irritated the Muslims.
While fighting Italy over a county I need to finally reform Rome pretty much every Sunni ruler charged their armies into Jerusalem on a Jihad. There's something in excess of 50000 troops running around there, my army has been drained by a few blunders and the Italians getting stupidly lucky. My own fault for not leading with overwhelming force I guess. My allies against the Jihad are feeding themselves piecemeal to the Sunnis rather than congealing into doomstacks of 10k+.
If I lose Jerusalem it'll be no big deal I guess, I can just Holy War to take it back in short order, but it'll be annoying to lose it just as I get the last of Ferrara.
Once I've got Rome together I'm going to have to start trying to wipe out the Sunni faith so this doesn't happen again I think. I can take any nation on individually and grind them down with sheer brutal numbers, but the coalesced mass of the Muslims still outnumbers me by a few tens of thousands.
Good news is that between my actions and those of my vassals a few Lord Mayors I made while handing out counties a while ago are being usurped and replaced by proper counts and dukes. Still need to revoke the theocracy of Latium though, but that's a job for later.