The chart is all technically true. Finland was united in a crown union with the Russian crown, when the tsar abdicated, the decision was made for the Finnish parliament to take up sovereignty in his abscence. Thus, in a sense, you could say that Finland maintained the claims of the Russian crown in that the same instrument of government was continued and responsible for the transition to a republican and independent Finnish government, while the Russians overthrew the old regime entirely and replaced it with the shiny new Soviet system.

No one takes it seriously though, it’s really just a kind of historical joke, and as the chart alludes to, there are more claimants to the Roman Empire than residents of the city.

Nothing of this is as clear-cut as it says here.

But all in all, it’s a ship-of-Theseus situation. Is something the Roman Empire if it doesn’t contain Rome, consists of land that was never occupied by Romans, uses a language that wasn’t spoken in the Roman Empire, doesn’t have any societal or political connections to the Roman Empire, doesn’t call itself the Roman Empire and ultimately is no empire?

In the case of Russia and then Finland it’s a case of “I once touched someone who touched someone who touched someone who touched the Queen, so I am now the Queen.”

And calling the Western Roman Empire illegitimate (even though it contained Rome) and then the Ottomans too, but calling the Russian Empire (which never had anything to do with the Roman Empire) legitimate is more than questionable.

All in all, a fun little meme, but no factual basis to back it up.