Princess Catherine Ivanovna of Russia

Her relation to Prince Philip makes her a second cousin, once removed of King Charles III of the United Kingdom.

Born in Pavlovsk Palace, she was the second child of Prince John Konstantinovich of Russia and Princess Helen of Serbia.

Catherine and her brother, Vsevolod, remained in the care of her grandmother, the Grand Duchess Elizaveta Mavriekievna of Russia.

On 18 July 1918, their father, Prince John, was killed, and their mother, Princess Jelena, was arrested and spent several months in Soviet prisons.

Donna Lydia married a writer, Count Giovanni Turgi Prosperi de' Serconforti (1906–1988),[4][5] who published an autobiographical novel, Una bellissima mamà (1983).