 In the peace treaty of 1721, the Russian czar allowed all prisoners in Russia to return home, except those who had converted to the Russian religion, as this was considered to make them Russian citizens; but as the Swedish slaves had been forced to convert to the orthodox faith by their masters, they were kept in Russia.If it could be proven that they had been forced to convert, they would sometimes be let free, but forced to stay as free Russian citizens instead; the forced conversions could generally not be proven.The story of Lovisa von Burghausen is the perhaps best known of the many women being taken as slaves during this war.