Source: united baltic duchy map by rarayn | Source: http://rarayn.deviantart.com/art/United-Baltic-Duchy-Map-279726197
1749 – Die Hertzogthümer Curland und Liefland by JG Schreibern | Source: http://commons.wikimedia.org/wiki/File:Die_Hertzogth%C3%BCmer_Curland_und_Liefland.jpg