Complex sentence: Přemysl Ottokar II (1253--78) married a German princess, Margaret of Babenberg, and became duke of Austria, thereby acquiring Upper and Lower Austria and part of Styria; he conquered the rest of Styria, most of Carinthia, and parts of Carniola.
Split into simpler sentences: Přemysl Ottokar II (1253--78) married a German princess, Margaret of Babenberg, and became duke of Austria. He conquered the rest of Styria, most of Carinthia, and parts of Carniola.