Catherine I of Russia to bribe the Ottoman grand vizier Baltacı Mehmet Pasha into allowing a retreat. Mehmet allowed the retreat, whether motivated by the bribe or considerations of trade and diplomacy. In any case Peter credited Catherine and proceeded to marry her again (this time officially) at Saint Isaac's Cathedral in St. Petersburg on 9 February 1712. Catherine was Peter's second wife; he had previously married and divorced Eudoxia Lopukhina, who had borne him the Tsarevich Alexis Petrovich. Upon their wedding, Catherine took the style of her husband and became Tsarina. When Peter elevated the Russian Tsardom to Empire, Catherine became Empress. The
Duke Peter Alexandrovich of Oldenburg Duke Peter Alexandrovich of Oldenburg Peter Alexandrovich of Oldenburg (Duke Peter Friedrich Georg von Oldenburg) (21 November 1868 – 11 March 1924) was the first husband of Grand Duchess Olga Alexandrovna of Russia, the youngest sister of Tsar Nicholas II. He was born in Saint Petersburg, the only child of Duke Alexander Petrovich of Oldenburg (1844–1932) and Eugénie Maximilianovna of Leuchtenberg (1845–1925). His mother was a granddaughter of Tsar Nicholas I of Russia through Nicholas's daughter, Grand Duchess Maria Nikolayevna, and his father was a great-grandson of Tsar Paul I of Russia through his paternal grandmother Grand Duchess Catherine Pavlovna.