decline and fall of Rome is popular and fairly self evident: there is no Roman Empire today and thus it must have declined and fallen.
but it is a relatively simple narrative (just 3 words, decline and fall) to encapsulate a complex series of events, changing institutions, and material conditions that occurred over multiple centuries spanning 3 different continents. even the wording, decline and fall, predisposes us to believe there is a waning period followed by total collapse when the reality can be an acute failure (fall) without ability to fully recover (decline) or frankly one and not the other.
it also primes us in ways to accept that decline and fall is inevitable. look, it is true that things change and that change can and often does include stuff that can be widely described as decline and fall, especially on the level of empire. but that makes us inclined to overlook material conditions and choices people made that eventually led to decline and fall.
what I'm getting at is we should also consider a narrative of crisis and recovery. that is fairly often an accurate broad description of empire without supposing a seemingly linear and inevitable decline. crisis (or crises) occurs and the systems try to recover. sometimes successfully, eventually not. but the emphasis is on material condition and the choices people make to respond to them.
crisis and recovery is also more widely applicable and comparable as a narrative history
Rome was sacked by the Gauls in 390BC. the city fell and yet this was not the fall of Rome. nearly 200 years later Hannibal marched across the Italian peninsula, raiding Roman towns and destroying multiple Roman armies over multiple years. Roman prosperity fell and some estimate Rome's population declined by some 10%. and yet this is not the decline of Rome
both however represent crisis and recovery. Romans chose to stay and rebuild after the 390 sack. they raised more armies and successfully defeated the Carthaginians in Hannibal's war
actually crisis and response may be a better wording. the hope is response brings recovery but it doesn't always succeed. still it prompts a better analysis of context for the events than decline and fall
some 800 years after the Gallic sack, Rome is sacked by the Goths. again the city falls, and yet that's not the fall of the empire either. it's another crisis on top of the many that had been hitting the empire for a while at that point. like it's not even the thing that caused the empire to fall, but rather another sign that the empire was weaker than it used to be
decline and fall doesn't even make sense of that sack (and yet the city and empire persist) in a really coherent manner whereas crisis and response does. decline and fall can only make some sense after everything's done and you're looking back on it. which ok fair, that's what we're doing with historical narrative. but it does mean you start to try to massage some things to better fit that narrative
crisis and response just requires you to know what happened in those moments. here's the crisis, and this is how they tried to address it. you don't need to try to apply a centuries long overarching narrative to events that don't actually line up like a neatly scripted story because that isn't what history is
