Defeat at Manzikert-Where do the Turks go?

[Herzen's love-child]

I'll put it this way: We can say that we can't say anything with certainty, or we can ask if there's any real reason for the Turks to invade Anatolia while busy in Syria and Egypt.

Well, perhaps after they slurp down Syria (and maybe Egypt).

As for the latter: The thread seems to me to be "the Byzantines either won Manzikert or it never happened".

That kind of implies more successful than OTL, not less.

Perhaps. The impetuous Romanus IV and the factions opposing him could have played out a different fate. I'll end here by saying that at Manzikert, I suspect the Turks wouldn't have been decisively defeated even if the treachery and bad luck afflicting Romanos could be butterflied away. To me, that begs the question, if it is a mere indecisive defeat for the Turks, would they revert to Plan A and head for Syria or would they now feel that the Byzantines were now such a threat that they must now be dealt with before doing so?
I think you need to butterfly Manzikert in its entirety (Alp isn't engaged by Romanus in an attempt to regain border fortresses and allowed to go South as he wanted to) to keep the Seljuqs out of Anatolia for any length of time.

But I now surrender to the OP's POD for future discussion purposes....