It may come as a surprise to most people, but from a historian's point of view it makes perfect sense to say that the Roman Empire truly cease to exist in 1918, when the German Empire, Austro-Hungarian and Ottoman empires were dismantled.
Let me explain. The Romans founded Europe's first empire. In 285, the empire was partitioned in a Western Roman Empire and an Eastern Roman Empire (later known as the Byzantine Empire). After the fall of the Western Roman Empire in 476, the Roman Catholic Church took the role of heir of the empire and quickly recognised the Frankish king Clovis I as the rightful heir of the Romans in Gaul and the defender of the Roman Catholic Church. In 800, Charlemagne was crowned "Emperors of the Romans" by the Pope in Rome with the title of "Emperor and Augustus", confirming that the Franks had now officially succeeded as Roman Emperors.
Charlemagne's grandson divided his empire in three, and the title of Holy Roman Emperor was eventually to stay with the German part of Charlemagne's empire, although French Kings kept a rightful claim to the title as partial heirs of Charlemagne too. This is why when Napoleon rose to power and crowned himself emperor he dismantled the Holy Roman Empire to assert his claim as heir of Charlemagne and of the Roman Empire. There could only be one rightful emperor at the same time. Since the crown of Holy Roman Emperor had been in the House of Habsburg for over three and a half centuries, the Habsburgs proclaimed themselves Emperors of Austria the same year as Napoleon planned his coronation. This was clearly an attempt to invalidate Napoleon's legitimacy.
When the French Empire was abolished in 1814, the Habsburgs could finally reclaim their rights as heirs of the Western Roman Empire unopposed. A competition between France and Austria now escalated in the 19th century. Louis-Napoleon Bonaparte intended to reclaim the title for France, and established the Second French Empire with himself as emperor under the name Napoleon III in 1852.
During that time, Germany was unified under the Hohenzollern, and Prussia defeated Austria in the Seven Weeks' War in 1866. This caused the collapse of the Austrian Empire and prompted the Habsburgs to rebrand themselves as Austro-Hungarian emperors, granting the Kingdom of Hungary the same status as Austria in 1867. From then on the Austro-Hungarian Empire was no longer regarded as the true heir of the Holy Roman Empire, but merely an alliance of two kingdoms. The Prussian king intended to get the title for himself, and had to defeat the only other claimant, Napoleon III. When this was achieved in the Franco-Prussian War in 1870, Napoleon III relinquished the title of emperor in favour of William of Hohenzollern.
In the meantime the Byzantine Empire had been taken over by the Ottomans, who came to regard themselves as the successors of the (Eastern) Roman Empire, hence their occasional use of the title Caesar (قیصر kaysar).
The Russians also decided that it might be nice to style themselves as Roman emperors, even though Russia was never a part of the Roman, Byzantine or Carolingian empire. They started calling themselves Czar, a corruption of Caesar from 1721. That was really just a way of attracting international attention on their rising power, but it is interesting that they also regarded the title of emperor as indissociable from that of Caesar and Rome.
In 1917, in the midst of World War I, the Bolshevik Revolution brought the Russian Empire to an end. By an ironic twist of fate, the three empires with claims as heirs of the Romans, namely Germany, Austro-Hungary and the Ottoman Empire, fought on the same side in WWI, and lost. Consequently, all three empires were dismantled at the same time, and with them all legitimate claim of succession to the Roman Empire disappeared. It can therefore be said that the Roman Empire truly came to an end in the aftermath of WWI, when all the empires descended from the Romans collapsed. If one date is to be remembered it should be that of 1 November 1922, when the Ottoman Empire was abolished.
Let me explain. The Romans founded Europe's first empire. In 285, the empire was partitioned in a Western Roman Empire and an Eastern Roman Empire (later known as the Byzantine Empire). After the fall of the Western Roman Empire in 476, the Roman Catholic Church took the role of heir of the empire and quickly recognised the Frankish king Clovis I as the rightful heir of the Romans in Gaul and the defender of the Roman Catholic Church. In 800, Charlemagne was crowned "Emperors of the Romans" by the Pope in Rome with the title of "Emperor and Augustus", confirming that the Franks had now officially succeeded as Roman Emperors.
Charlemagne's grandson divided his empire in three, and the title of Holy Roman Emperor was eventually to stay with the German part of Charlemagne's empire, although French Kings kept a rightful claim to the title as partial heirs of Charlemagne too. This is why when Napoleon rose to power and crowned himself emperor he dismantled the Holy Roman Empire to assert his claim as heir of Charlemagne and of the Roman Empire. There could only be one rightful emperor at the same time. Since the crown of Holy Roman Emperor had been in the House of Habsburg for over three and a half centuries, the Habsburgs proclaimed themselves Emperors of Austria the same year as Napoleon planned his coronation. This was clearly an attempt to invalidate Napoleon's legitimacy.
When the French Empire was abolished in 1814, the Habsburgs could finally reclaim their rights as heirs of the Western Roman Empire unopposed. A competition between France and Austria now escalated in the 19th century. Louis-Napoleon Bonaparte intended to reclaim the title for France, and established the Second French Empire with himself as emperor under the name Napoleon III in 1852.
During that time, Germany was unified under the Hohenzollern, and Prussia defeated Austria in the Seven Weeks' War in 1866. This caused the collapse of the Austrian Empire and prompted the Habsburgs to rebrand themselves as Austro-Hungarian emperors, granting the Kingdom of Hungary the same status as Austria in 1867. From then on the Austro-Hungarian Empire was no longer regarded as the true heir of the Holy Roman Empire, but merely an alliance of two kingdoms. The Prussian king intended to get the title for himself, and had to defeat the only other claimant, Napoleon III. When this was achieved in the Franco-Prussian War in 1870, Napoleon III relinquished the title of emperor in favour of William of Hohenzollern.
In the meantime the Byzantine Empire had been taken over by the Ottomans, who came to regard themselves as the successors of the (Eastern) Roman Empire, hence their occasional use of the title Caesar (قیصر kaysar).
The Russians also decided that it might be nice to style themselves as Roman emperors, even though Russia was never a part of the Roman, Byzantine or Carolingian empire. They started calling themselves Czar, a corruption of Caesar from 1721. That was really just a way of attracting international attention on their rising power, but it is interesting that they also regarded the title of emperor as indissociable from that of Caesar and Rome.
In 1917, in the midst of World War I, the Bolshevik Revolution brought the Russian Empire to an end. By an ironic twist of fate, the three empires with claims as heirs of the Romans, namely Germany, Austro-Hungary and the Ottoman Empire, fought on the same side in WWI, and lost. Consequently, all three empires were dismantled at the same time, and with them all legitimate claim of succession to the Roman Empire disappeared. It can therefore be said that the Roman Empire truly came to an end in the aftermath of WWI, when all the empires descended from the Romans collapsed. If one date is to be remembered it should be that of 1 November 1922, when the Ottoman Empire was abolished.