Germany was divided into many kingdoms, principalities, grand duchies, etc. before unification in 1871. The German ruling houses provided an ample supply of wives for royal and noble houses all over Europe, but especially in Russia. Princess Alexandra Friederike Henriette of Saxe-Altenberg married the forward-thinking Grand Duke Konstantin of Russia in one of those marriages, taking the name Alexandra Iosifovna. She was not as progressive as her husband, contributing to the failure of their marriage after some apparently good years or even decades according to her Wikipedia article (located here).