[1] In the start of 1808, when Oldenburg was occupied by French and Dutch troops, George was sent to Russia to stay with his relatives, the Russian Imperial family.

[3] The events behind their marriage began when Napoleon Bonaparte, hoping to secure a Russian alliance as well as a male heir, hinted his desire to marry Catherine after finalizing his divorce with Empress Joséphine.

[3] This so horrified the Russian imperial family that Catherine's mother immediately arranged her marriage to her cousin, Duke George.

The day the marriage occurred, Duke George received the style Imperial Highness and was appointed the governor-general of the three central provinces of Tver, Yaroslavl and Novgorod.

As George was a younger son with little prospects of inheriting the Grand Dukedom of Oldenburg, he and Catherine lived in Tver, Russia.