Princess Maria's great uncle
Prince Pyotr Dmitrievich S-M 1857-1914
(who was Minister of the Interior in St. Petersburg, Russia, in 1905).

Maria's great-grandfather, Prince Nicolai Ivanovitch Sviatopolk-Mirski, was the last owner of Mir Castle

Princess Maria's Grandparents

Sviatopolk-Mirski family Estate at Vitebsk.
The man standing on the left is Maria's
grandmother's second husband: Pavel Kondratenko