The Grand Duke George Romanov of Russia married Italian Rebecca Virginia Bettarini at Saintt Isaac's Cathedral in St Petersburg on Friday.
It was the first imperial wedding to take place in Russia since the Russian Revolution more than a century ago.
Aristocrats from across Europe travelled to the city to celebrate with the couple.
Romanov is the only son of Grand Duchess Maria Vladimirovna and Prince Franz Wilhelm of Prussia, and a third great-grandson of the Emperor Alexander II of Russia.
The grand duke was born in Spain and was educated in Oxford. Now he lives in Moscow and works on philanthropic projects.
Rebecca Bettarini is the daughter of Italian diplomat Roberto Bettarini and is the director of the Russian Imperial Foundation. She recently became Russian Orthodox.
The last royal wedding took place on November 26, 1895, also in St Petersburg.
It was the wedding of the Tsar Nicholas II of Russia and his German fiancee, Princess Alix of Hesse, a granddaughter of the Queen Victoria.