the historical region of westphalia, which included the duchy of westphalia and other regions, was distributed since 1810 to the french empire, the kingdom of westphalia, the grand duchy of berg and the grand duchy of hesse. it was renamed after the congress of vienna on the basis of "the establishment of provincial authorities" between prussia, hanover and oldenburg on 30 april 1815. the principality of lippe was the only one of the old westphalian territories to retain its independence. prussia received the largest part and also included the non-westphalian territories of wittgenstein and the sub-principality of siegen. on top of that, the siegerland, which was first occupied by the province of the lower rhine. after 1850, the city of lippstadt, which had previously belong to the prussian-lippish condominium, was still located in the province of westphalia. since the core area was the former duchy of westphalia, king frederick william assumed the title of duke of westphalia and angria and added it to the prussian royal titles.