Frankish Empire is a completely different entity that was established after collapse of the Western Roman Empire by Germanic migratory tribe. Though they actually claimed to be a legitimate inheritors of Rome after Charlemagne's coronation as the Emperor of the Romans in 800.
Alongside what CyborgMarx said, the Frankish Empire were German invaders rather than any sort of continuation of the Roman Empire. They also didn't really control Rome, which stayed in the hands of the Pope.
But yes, the intent was basically for it to be the successor to the Roman Empire. The Pope crowned Charlemagne as emperor because the Byzantines had an empress regnant which the Pope saw as illegitimate and therefore saw the title of emperor as forfeited.
I don't think he was actually called Roman emperor specifically (Nevermind, like kleeon said he was called "Emperor of the Romans"), but at that point "emperor" (well, "imperator") had only ever referred to the Roman emperor. It wasn't really a generic word like it is today.
Regardless, afaik it's generally agreed by historians that the Byzantine Empire was the Roman Empire (not just a successor, but a continuation). And that the Frankish Empire (and later "Holy" "Roman" "Empire") was not, nor was it a true successor.
Charlemagne was King of the Franks and was crowned as Emperor of the Romans in 800. He was campaigning against the greek-speaking romans based in Constantinople that were ruled by Empress Irene, so the pope declared the throne vacant, and pronounced Charlemagne emperor. despite the warfare, there was a bit of mutual acknowledgement like there had been when the original roman empire was split in two.
the period from Charlemagne (maybe his father Pepin, even) to the death of Louis the Pious are sometimes called a 'renaissance', and witnessed a real expansion in sophistication of state administration & the use of writing which had declined on the breakup of the earlier roman state. things unmistakably medieval like the establishments of monasteries, the church as a governing apparatus, and the idea of united 'christendom' have their origin in the period. it wasn't quite feudal disfunctional, but not the sophistication of antiquity either. Charlemagne went to his death-bed unable to write, even though people in his orbit created a large corpus of surviving documents.
regarding names: from ~460-751 ce there's one or more Frankish kingdoms, the most prominent being the dynasty of Merovech--"Merovingians, Merovingian Kingdom" but it was sometimes split & there were other dynasties earlier. Merovingians are remembered by regnal hair, the King and princes never cut their hair, except when deposed or defeated. From 751 the last heir of that dynasty was deposed by the "Mayor of the Palace", the father of Charlemagne, Pepin. 751-840 there was mostly a single kingdom under a member of the "Carolingian" (after Charlemagne) dynasty---but after 800 ce that man also called himself "Emperor".
so from the 400s--->800 "Frankish Kingdom" is applicable, and 'Empire' is sometimes used too. From 800-->840 there's 1 "Frankish Empire", after which it breaks up and there might be one or multiple, depending on what you're talking about. then the 400s-->751 period is "Merovingian" and the 751-->987 is "Carolingian". the "Holy Roman Empire" can be said to have been started with Charlemagne in 800, but usually in books they'll use the other terms for these early periods, and switch to "Holy Roman" from Otto I when the title became firmly associated with Germany and Italy, to the exclusion of modern France.
This just looks like essentially the Western Roman Empire.
What's the dividing line between calling it the Roman Empire vs the Frankish? (Actual question)
Frankish Empire is a completely different entity that was established after collapse of the Western Roman Empire by Germanic migratory tribe. Though they actually claimed to be a legitimate inheritors of Rome after Charlemagne's coronation as the Emperor of the Romans in 800.
Alongside what CyborgMarx said, the Frankish Empire were German invaders rather than any sort of continuation of the Roman Empire. They also didn't really control Rome, which stayed in the hands of the Pope.
But yes, the intent was basically for it to be the successor to the Roman Empire. The Pope crowned Charlemagne as emperor because the Byzantines had an empress regnant which the Pope saw as illegitimate and therefore saw the title of emperor as forfeited.
I don't think he was actually called Roman emperor specifically(Nevermind, like kleeon said he was called "Emperor of the Romans"), but at that point "emperor" (well, "imperator") had only ever referred to the Roman emperor. It wasn't really a generic word like it is today.Regardless, afaik it's generally agreed by historians that the Byzantine Empire was the Roman Empire (not just a successor, but a continuation). And that the Frankish Empire (and later "Holy" "Roman" "Empire") was not, nor was it a true successor.
Charlemagne was King of the Franks and was crowned as Emperor of the Romans in 800. He was campaigning against the greek-speaking romans based in Constantinople that were ruled by Empress Irene, so the pope declared the throne vacant, and pronounced Charlemagne emperor. despite the warfare, there was a bit of mutual acknowledgement like there had been when the original roman empire was split in two.
the period from Charlemagne (maybe his father Pepin, even) to the death of Louis the Pious are sometimes called a 'renaissance', and witnessed a real expansion in sophistication of state administration & the use of writing which had declined on the breakup of the earlier roman state. things unmistakably medieval like the establishments of monasteries, the church as a governing apparatus, and the idea of united 'christendom' have their origin in the period. it wasn't quite feudal disfunctional, but not the sophistication of antiquity either. Charlemagne went to his death-bed unable to write, even though people in his orbit created a large corpus of surviving documents.
regarding names: from ~460-751 ce there's one or more Frankish kingdoms, the most prominent being the dynasty of Merovech--"Merovingians, Merovingian Kingdom" but it was sometimes split & there were other dynasties earlier. Merovingians are remembered by regnal hair, the King and princes never cut their hair, except when deposed or defeated. From 751 the last heir of that dynasty was deposed by the "Mayor of the Palace", the father of Charlemagne, Pepin. 751-840 there was mostly a single kingdom under a member of the "Carolingian" (after Charlemagne) dynasty---but after 800 ce that man also called himself "Emperor".
so from the 400s--->800 "Frankish Kingdom" is applicable, and 'Empire' is sometimes used too. From 800-->840 there's 1 "Frankish Empire", after which it breaks up and there might be one or multiple, depending on what you're talking about. then the 400s-->751 period is "Merovingian" and the 751-->987 is "Carolingian". the "Holy Roman Empire" can be said to have been started with Charlemagne in 800, but usually in books they'll use the other terms for these early periods, and switch to "Holy Roman" from Otto I when the title became firmly associated with Germany and Italy, to the exclusion of modern France.
Lack of cities, mobility, bulk international trade, a standardized army, plus significant population decline