Ioann Konstantinovich was born in
Pavlovsk Palace, as a
Grand Duke of Russia with the style
Imperial Highness, but at the age of just 9 days, an Ukaz of his cousin Emperor
Alexander III of Russia stripped him of that title, as the Ukaz amended the House Law by limiting the grand-ducal title only to legitimate
patrilineal grandsons of a reigning emperor. As a result, he received the new title,
Prince of the Imperial Blood (Prince of Russia) with the style of
Highness. He once entertained the possibility of becoming an
Orthodox monk, but eventually fell in love with
Princess Helen of Serbia, the eldest child and only surviving daughter of
King Peter I of Serbia by his wife,
Princess Zorka of Montenegro, whose aunts were
Grand Duchess Militza,
Grand Duchess Anastasia of Russia and
Queen Elena of Italy. They married on 2 September 1911, and Helen took the name Princess Yelena Petrovna of
Russia. As a daughter of the reigning King, after the marriage, she retained her style of
Royal Highness and as such she had the right to receive foreign diplomats in her own right, unlike her husband. They had a son,
Prince Vsevolod Ivanovich (20 January 1914 – 18 June 1973), and a daughter,
Princess Yekaterina Ivanovna (12 July 1915 – 13 March 2007), who was the last member of the Imperial Family to be born before the fall of the dynasty, and was ultimately to become the last surviving uncontested dynast of the
Imperial House of Russia. ==Revolution and death==