Maria Mikhailovna Berg, born Princess Dolgorukova, was the younger sister of the morganatic wife of Tsar Alexander II, Princess Ekaterina Yurievskaya. At one point, Maria acted as an intermediary in her sister's secret relationship with the sovereign, and later became the godmother of their youngest daughter, Ekaterina.

Born on April 11, 1849, Maria was very close to her sister Ekaterina and spent much time with her during childhood. After receiving a good home education, they both entered the Smolny Institute for Noble Maidens, where Ekaterina met Emperor Alexander II. At the beginning of their romance, Maria delivered love letters from the sovereign to her sister.

Once, their close relationship was threatened by Ekaterina's jealousy, as she suspected Alexander II of having feelings for the more attractive Maria. As a result, Maria was sent to Kyiv. Later, the sisters reconciled, and Maria became the godmother of her youngest niece.

Maria's personal life did not go well for a long time. The sovereign wanted to marry Prince Vyazemsky to his relative, but he refused, and in 1870, Maria married Prince Meshchersky, with whom she had a daughter. However, the prince was more interested in gambling than in his young wife. He was a brave officer and went to the Russo-Turkish War, where he died at Shipka, honored with two monuments in Bulgaria.

Maria found happiness in her second marriage to Count Georgy Berg. They had two sons. Maria lived for 57 years and passed away on February 12, 1907. She was buried in the Russian cemetery in Nice.