Both Schleswig and Holstein had been ruled through institutions separate from the rest of the Danish Kingdom. On March 27, 1848, Frederick VII of Denmark announced to the people of Schleswig the promulgation of a liberal constitution under which the duchy, while preserving its local autonomy, would become an integral part of Denmark. This led to an open uprising by Schleswig-Holstein's large German majority in support of independence from Denmark and of close association with the German Confederation. The military intervention of the Kingdom of Prussia supported the uprising: the Prussian army drove Denmark's troops from Schleswig and Holstein, beginning the First Schleswig War (1848–51), which ended in a Danish victory at Idstedt; with the London Protocol, the international community agreed on the Duchies' status.