I often wonder what became of the children born to Tsar Alexander II and Princess Katherine Dolgoruky (may have misspelt her name here!), his mistress and later second wife after the tsarina's death. I think one child died in infancy, maybe a little older. Princess Dolgoruky died in the 1920s in exile I believe.
Some of the descendants of
Tsar Alexander II and
HSH Princess Catherine Dolgorukova, Princess Yurievskaya, are still alive.
Boris was the son that only lived a few weeks.. but their other children survived to adulthood. After Alexander died, Catherine eventually moved with her children to Paris, and also bought a home in Nice, where she died in 1922.
The children:
HSH Prince George Alexandrovich Yurievsky (1872-1913) married
Countess Alexandra von Zarnekau (1883-1957), and although they were divorced did manage to produce a son,
HSH Prince Alexander Yurievsky (1900-1988).
George's grandson is
HSH Prince George Yurievsky. He was born in 1961 and was last known to be married.. whether he has any children is not known to me.
HSH Princess Olga Alexandrovna Yurievskaya (1873-1925) married
Graf Georg von Merenberg (1871-1948), and had three children. Georg von Merenberg was the grandson of Alexander Pushkin. Their eldest son lived less than a year, but
Graf Georg Michael and
Gräfin Olga both married and had issue.
(The current Marquess of Milford Haven is a descendant of Georg von Merenberg's sister Sophie, who married morganatically Grand Duke Mikhail Mikhailovich of Russia. She was created Countess de Torby.)
Olga's granddaughter,
Gräfin Clothilde von Merenberg is the last living member of the male line of von Merenberg. She has three sons. Olga's grandson,
Count Alexander Loris-Melikov is married with four children born in the early 60's- so he likely has grandchildren by now.
HSH Princess Catherine Alexandrovna Yurievskaya (1878-1959) first married
Prince Alexander Bariatinsky (1870-1910), with whom she had two sons,
Prince Andrei Bariatinsky (1902-1931) and
Prince Alexander Bariatinsky (b. 1905).
Although Andrei died relatively young, he was married and had a daughter,
Princess Elena Bariatinsky, in 1927. She was twice married but had no known children. She died in 1988.
I have no information on Prince Alexander or whether he had a family.. I feel sure he is probably deceased by now.
HSH Princess Catherine Yurievskaya married
Sergei Platonvich Obolensky, Prince Obolensky (1890-1978) after her first husband's death. They had no children, and Sergei left her in 1924 to marry Ava Alice Muriel Astor, the daughter of John Jacob Astor IV.
(and though they had two children, Sergei's second marriage collapsed in 1932. Ava would go on to marry three more times and have two additional children.)
Catherine spent her final years at Hayling Island, England, receiving a small pension from Queen Mary until HM's death in 1953. She died at Hayling in 1959 and is buried in the village of Northney.
One of Tsar Alexander II's other illegitimate children, Antoinette Bayer, was married in 1881 to Richard Flemyng St. Leger, the grandson of the 1st Viscount Doneraile. Her daughter, Joan de St. Leger, married and left three children - Richard Muller (1915-1977), Charles Muller (b. 1919) and Johanna Muller (b. 1920) - who all have issue (and probably grandchildren and great grandchildren). Joan died in 1955 - her mother Antoinette died in 1948.