Ferdinand Kettler
Ferdinand Kettler was the Duke of Courland and Semigallia from 1730 to 1737.
Ferdinand Kettler was born on November 1, 1655, in Jelgava, Latvia. He and his family, who had been held captive by the Swedes in Riga. They were moved to Ivangorod, Russia and held there between 1658 and 1660.
Source: Wikipedia