Using any POD you can think of that will work, your challenge is to make a Slavic Greece.
Using any POD you can think of that will work, your challenge is to make a Slavic Greece.
The Byzantines continue to project power primarily eastward into the eleventh century, with Basil II or whoever being more concerned about consolidating conquests in Syria and Mesopotamia, as well as expanding in Armenia, than he is in destroying Bulgarian power in the Balkans. You'd probably still get Byzantine holdouts in places like Thessalonica and the Peloponese, but a large chunk of mainland Greece would never be re-absorbed into a Greek speaking world.
Hm, I might give you an even earlier POD - A.D. 626.Actually I am of the opinion it need's an earlier PoD with the failure of the success of Macedonian dynasty in late 9th and early 10th century.
Hm, I might give you an even earlier POD - A.D. 626.
In OTL allied with the Avars, the Persians made a final attempt to take Constantinople in 626, but were defeated there.
In my proposed ATL the Avars took Constantinople in 626 with the help of the Persians. That's the POD.
You may read further in this thread.
Or we might get a little milder on the Greeks. Constantinople is not taken, but Heraclius is killed and disgraceful treaty signed by the Roman state - they give all their lands in Europe to the Avars (except Constantinople and some insignificant tiny aclaves)
Avars are not Slavic of course, but they've got a lot of Slavic subjects who would settle all over Greece.
And over time they'd be assimilated into the Slavic speaking population, a la the Bulgars of Asparukh.