Russian Empire
Though the Empire was only officially proclaimed by Tsar Peter I following the Treaty of Nystad (1721), some historians would argue that it was truly born either when Ivan III of Russia conquered Veliky Novgorod in 1478, or when Ivan the Terrible conquered the Khanate of Kazan in 1552. According to another point of view, the term "Tsardom", which was used after the coronation of Ivan IV in 1547, was already a contemporary Russian word for empire.
House of Romanov
Grand Duke Kirill Vladimirovich, a male-line grandson of Tsar Alexander II, claimed the headship of the deposed Imperial House of Russia, and assumed, as pretender, the title "Emperor and Autocrat of all the Russias" in 1924 when the evidence appeared conclusive that all Romanovs higher in the line of succession had been killed. Kirill was followed by his only son Vladimir Kirillovich. Vladimir's only child, Maria Vladimirovna (born 1953), claims to have succeeded her father. The only son of her marriage with Prince Franz Wilhelm of Prussia, George Mikhailovich, is her heir apparent. The Romanov Family Association (RFA) formed in 1979, a private organization of most of the male-line descendants of Emperor Paul I of Russia (other than Vladimir Kirillovich, Maria Vladimirovna and her son) acknowledges the dynastic claims to the throne of no pretender, and is officially committed to support only that form of government chosen by the Russian nation. However the RFA's former president, Nicholas Romanovich, along with his brother Dimitri and some other family members, have repudiated the transfer of the dynasty's legacy to the female-line, contending that his claim is as valid as that of Maria Vladimirovna or her son. A great-grandson of Kirill's who is not a male-line Romanov, Prince Karl Emich of Leiningen, also claims to be the rightful representative of the Romanov Imperial heritage and has become the founder of Romanov Empire.