sasanids

What is the latest possible PoD for some form of Egyptian religion to be restored/founded (in Egypt, of course)? It must be an Egyptian religion involving worship of at least one native Egyptian deity IE Ra, Set, Isis, Osiris, etc, not a syncretic religion like Hellenism and not a composite...

With a POD no earlier than 600 AD wank the Sassanid Empire and Zarathustrianism as much as possible.

The Battle of Dara was a quite important battle during the Roman-Persian Iberian War, the Roman forces successfully repelled the Persian offensive, gave rise to Belisarius and eventually lead to a stalemate of the war, where Rome agreed on an "Eternal Peace" (that lasted 8 years) with Persia and...

The period would be the Military Anarchy; perhaps Shapur decisively defeats the Romans at Anatolia in 260 instead of the other way around, and besieges (EDIT: Byzantium/Augusta Antonina/the Bosporus, brainfart) whilst also breaking into Syria and endnagering the grain supply, forcing Rome to...