Conquest was released in England as Marie Waleska, the name of the real-life historical personage portrayed by Greta Garbo. The film begins in 1807, when Marie, a Polish countess, is dispatched by her country to meet with Emperor Napoleon Bonaparte (Charles Boyer). Marie has been encouraged to press for Polish independence by whatever means possible--and though no one comes out and says as much, it is understood that she will offer herself sexually to the promiscuous Napoleon. She dutifully becomes Bonaparte's mistress, bears his child, and--almost as an afterthought--falls in love with him. Thanks to the political chicanery of Talleyrand (Reginald Owen), Napoleon is obliged to marry Hapsburg princess Marie Louise, and Marie is cast aside, her usefulness at an end. Only after Napoleon has been exiled to Elba in 1815 is he reunited with Marie and their son (Scotty Beckett). Though it stands up pretty well today, Conquest was a flop in 1937, and the beginning of the end of Garbo's screen career.
~ Hal Erickson, All Movie Guide