rome's rivals

With a PoD between the Year of The Four Emperors (69 AD) and the death of Marcus Aurelius (180 AD), what could be the worst case scenario for the integrity and stability of the "late Principate" Roman Empire? For a bit of context, OTL's 2nd Century AD saw a few invasions of Roman territory...

What if the awesomely-named king Perseus of Macedon, son of the previously defeated Philip V, had managed to successfully fight off the Romans at the Battle of Pydna (168 BCE), preserving the Macedonian hegemony over Greece and perhaps even expanding it? Would the stage be set for another, more...

What are your favorite Rome-screw scenarios? Basically, the ones in which Rome's supposed favour amongst the gods fails them at crucial moments in military and political history? Covering the period between the founding of Rome (753 BCE) and the fall of the city to Odoacer (476 AD). I'll throw...

Back in the late 60's BCE, there was a long-standing rivalry within Celtic Gaul between the Aedui, who were building an empire of sorts, and the Sequani and Arverni, who were, in turn, threatened by the expansion of the (Roman-allied) Aedui. The latter party invited a king of the Suebi Germanic...

What if the Roman Republic lost most of the key battles of the Cimbrian War (maybe through Gaius Marius dying in his fight against Jugurtha of Numidia), in the late 2nd century BCE? What would happen next? Could the Cimbri and the Teutones invade the italian peninsula and sack Rome? Could they...

(I already made a thread on the Battle of The Catalaunian Plains a few months ago, but i think it's already too old to be bumped.) What if Attila, The Hun, had managed to defeat Flavius Aetius and his germanic foederati allies at the Catalaunian Plains in 451 AD? Would this spill an earlier end...

IOTL, roman forces clashed with sassanian persian forces at the Battle of Edessa, in 260 AD. The persians ended up winning, and even captured the roman emperor, Valerian, who was held captive by the persian king Shapur until his death. So, what if the battle had a reverse outcome, with Shapur...

https://civilianmilitaryintelligencegroup.com/14742/the-battle-of-telamon-if-rome-lost-this-battle-it-might-not-have-survived IOTL, some celtic tribes were advancing across northern Italy right after the First Punic War, where they encountered the forces of the roman republic in a large battle...

What if Carthage simply didn't exist? The Phoceanian traders and Dido (first queen of Carthage) didn't build Carthage or settle that area of North Africa (modern day Tunisia). What would the effects on the Mediterranean be without a Carthaginian trade power? Could a Rome as we know it even...

What if Rome never dominated the Mediterranean like it did in OTL? What if other polities (like Carthage and Ptolemaic Egypt) survived Rome's rise and flourish to become her rivals? Or maybe some of the Germanic tribes adopt some aspects of Roman culture and formed their own states that can...