The people are historically named Moravians, a subgroup of Czechs, the other group being called Bohemians. Moravia also had been home of a large German-speaking population until their expulsion in 1945. The land takes its name from the Morava river, which runs from its north to south, being its principal watercourse. Moravia's largest city and historical capital is Brno. Before being sacked by the Swedish army during the Thirty Years' War, Olomouc served as the Moravian capital, and it is still the seat of the Roman Catholic Archdiocese of Olomouc.