Sweden

From Viking traders on the eastern rivers to a Baltic empire, a long neutrality, and at last into NATO.

Sweden's history runs from the seafaring Norsemen who carved trade routes east toward Byzantium and the Caliphate, through a medieval Christian kingdom drawn into and then out of a Scandinavian union, to a brief but dazzling career as a great power straddling the Baltic. The modern Swedish state is conventionally dated to 1523, when Gustav Vasa was elected king after a war of liberation that shattered the Danish-led Kalmar Union, and went on to break with Rome and build a centralised Lutheran monarchy. In the seventeenth century, under Gustavus Adolphus and his successors, Sweden intervened decisively in the Thirty Years' War, won territory at the Peace of Westphalia and seized Scania from Denmark, becoming the dominant power of the north until the catastrophe of Poltava in 1709 brought the empire down. The nineteenth century reshaped Sweden again: it lost Finland to Russia in 1809, gained and then peacefully relinquished Norway, founded the Bernadotte dynasty, and from 1814 embraced a long tradition of neutrality. That tradition outlasted two world wars and the Cold War, until Russia's invasion of Ukraine led Sweden to abandon two centuries of non-alignment and join NATO in March 2024.