The monarchy of Sweden is centred on the monarchical head of state of Sweden, by law a constitutional and hereditary monarchy with a parliamentary system. There have been kings in what now is the Kingdom of Sweden for more than a millennium. Originally an elective monarchy, it became a hereditary monarchy in the 16th century during the reign of Gustav Vasa, though virtually all monarchs before that belonged to a limited and small number of political families which are considered to be the royal dynasties of Sweden.
The official continuous count usually begins with the kings who ruled both Svealand and Götaland as one kingdom. Sweden's monarchy is amongst the oldest in the world, with a regnal list stretching back to the tenth century, starting with Eric the Victorious; the Swedish monarchy has, for the past thousand years, undergone cycles of decline and strengthening, culminating in the modern constitutional monarchy.
