Olga Constantinovna of Russia (September 3, 1851 – June 18, 1926) was Queen consort of the Hellenes as the wife of King George I. She was briefly the regent of Greece in 1920.

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A member of the Romanov dynasty, she was the daughter of Grand Duke Constantine Nikolaievich and his wife, Princess Alexandra of Saxe-Altenburg, the fifth daughter of Joseph, Duke of Saxe-Altenburg and Amelie Theresa Luise, Duchess of Württemberg. She is an ancestor of the British, Greek, Romanian, Yugoslavian and Spanish Royal Families through her elder daughter Olga.

Through her father, Olga was a granddaughter of Emperor Nicholas I, a niece of Emperor Alexander II and first cousin of Emperor Alexander III.

She spent her childhood in Saint Petersburg, Poland and the Crimea. Her father was a younger brother of Alexander II, and her mother was considered one of the most intelligent and elegant women of the court. Olga was particularly close to her older brother, Nicholas, and was one of the few members of the imperial family to keep in touch with him after he was banished to Tashkent.

Princess Alexandra of Saxe-Altenburg (Mother)

The young King George I of Greece visited Russia in 1863 to thank Olga’s uncle Emperor Alexander II for his support during George’s election to the throne of Greece. Whilst there, George met the then twelve-year-old Olga for the first time.

George visited Russia again in 1867 to meet with his sister Dagmar, who had married Tsarevitch Alexander (later Alexander III) the year before. He was determined to find a wife and the idea of an alliance with a Russian grand duchess, born into the Eastern Orthodox Church, appealed to him.

Olga fell in love with George, but she was nevertheless anxious and distraught at the thought of leaving Russia. Her father was initially reluctant to agree to their marriage, thinking that at the age of fifteen she was too young and, being close to his daughter, concerned by the distance between Greece and Russia.

For her part, Grand Duchess Alexandra was much more enthusiastic than her husband and, when some members of the imperial family noted the extreme youth of her daughter, she replied that Olga would not always be as young. Eventually, it was decided that Olga and George would marry when she had reached her sixteenth birthday. Meanwhile, she would continue her schoolwork until her wedding day.

Olga and George married at the chapel of the Winter Palace in Saint Petersburg on October 27, 1867. After five days of festivities, they spent a brief honeymoon at Ropsha, south-west of Saint Petersburg. Over the following twenty years, they had eight children.

At first, she felt ill at ease in the Kingdom of Greece, but she quickly became involved in social and charitable work. She founded hospitals and schools, but her attempt to promote a new, more accessible, Greek translation of the Gospels sparked riots by religious conservatives.

On the assassination of her husband in 1913, Olga returned to Russia. When the First World War broke out, she set up a military hospital in Pavlovsk Palace, which belonged to her brother. She was trapped in the palace after the Russian Revolution of 1917, until the Danish embassy intervened, allowing her to escape to Switzerland. Olga could not return to Greece as her son, King Constantine I, had been deposed.

In October 1920, she returned to Athens on the fatal illness of her grandson, King Alexander. After his death, she was appointed regent until the restoration of Constantine I the following month. After the defeat of the Greeks in the Greco-Turkish War of 1919–22 the Greek royal family were again exiled and Olga spent the last years of her life in the United Kingdom, France and Italy.